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Department of Civil & Environmental Engineering, Hanyang University, 222 Wangsimni-Ro, Seoul 04763, Republic of Korea
Dr. Deepak Kukkar
Department of Civil & Environmental Engineering, Hanyang University, 222 Wangsimni-Ro, Seoul 04763, Republic of Korea
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Advanced Nanomaterials for Sensing Applications

Abstract submission deadline
closed (31 December 2022)
Manuscript submission deadline
closed (31 December 2023)
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Topic Information

Dear Colleagues,

Advanced nanomaterials (e.g., metal–organic frameworks, noble metal nanoparticles, semiconductor quantum dots) exhibit numerous unique properties such as size-dependent opto-electronic features, a high surface area to volume ratio, robust and stable structures, pendent functional groups, discrete signal output, and excellent sensitivity. These properties enable the aforementioned nanomaterials to be used in the design and development of sensors for the detection of numerous targets, such as heavy metals, organic pollutants, pathogenic microbes, biomarkers, metabolites, etc. Further, these targets can be detected using various sensing methodologies such as electrochemical detection, optical, fluorescence, surface plasmon resonance, colorimetry, etc. In view of the diverse properties and sensing applications of the new nanostructured materials, we cordially invite you to contribute to this Topic entitled, “Advanced Nanomaterials for Sensing Applications”. The major goal of this topic is to collect very recent findings (original research, communications, or review articles) and developments in the synthesis and sensing applications of advanced nanomaterials (e.g., metal–organic frameworks, noble metal nanoparticles, transition metals and metal oxides, semiconductor inorganic nanocrystals, carbon-based nanomaterials). Prospective authors may consider the various sensing applications of the above-mentioned nanomaterial categories for the detection of this catalysis, the sensing of diverse targets (e.g., environmental pollutants, microbes, pathogens, explosives, biomarkers, metabolites).

Prof. Dr. Ki-Hyun Kim
Dr. Deepak Kukkar
Topic Editors

Keywords

  • nanomaterials
  • advanced materials
  • sensing
  • biosensing
  • chemosensing
  • optical sensing
  • electrochemical sensing

Participating Journals

Journal Name Impact Factor CiteScore Launched Year First Decision (median) APC
Applied Sciences
applsci 		2.5 5.3 2011 17.8 Days CHF 2400
Biosensors
biosensors 		4.9 6.6 2011 17.1 Days CHF 2700
Materials
materials 		3.1 5.8 2008 15.5 Days CHF 2600
Nanomaterials
nanomaterials 		4.4 8.5 2010 13.8 Days CHF 2900
Sensors
sensors 		3.4 7.3 2001 16.8 Days CHF 2600

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Published Papers (95 papers)

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11 pages, 2844 KiB  
Communication
Generalized Electron Emission Theory for One-Dimensional Conducting Materials
by Heetae Kim, Chang-Soo Park and Soon Jae Yu
Appl. Sci. 2024, 14(7), 2993; https://doi.org/10.3390/app14072993 - 2 Apr 2024
Cited by 2 | Viewed by 1170
Abstract
This research focuses on exploring generalized electron emissions in one-dimensional conducting materials, specifically examining field emission and thermionic emission. Additionally, this study investigates one-dimensional thermal radiation. The current density is derived for both one-dimensional thermionic emission and one-dimensional field emission. A generalized current [...] Read more.
This research focuses on exploring generalized electron emissions in one-dimensional conducting materials, specifically examining field emission and thermionic emission. Additionally, this study investigates one-dimensional thermal radiation. The current density is derived for both one-dimensional thermionic emission and one-dimensional field emission. A generalized current density in one dimension is devised, taking into account arbitrary accelerating fields and temperature conditions. The formula for the one-dimensional current density is depicted with accelerating field and temperature across various work function materials. The emission current is represented as a function of temperature for various electric fields. The emission current is also represented as a function of the electric field for various temperatures. Full article
(This article belongs to the Topic Advanced Nanomaterials for Sensing Applications)
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15 pages, 4663 KiB  
Article
Photocatalytic Oxidization Based on TiO2/Au Nanocomposite Film for the Pretreatment of Total Phosphorus (TP)
by Jiajie Wang, Seung-Deok Kim, Jae-Yong Lee, June-Soo Kim, Noah Jang, Hyunjun Kim, Da-Ye Kim, Yujin Nam, Maeum Han and Seong-Ho Kong
Appl. Sci. 2024, 14(5), 1774; https://doi.org/10.3390/app14051774 - 22 Feb 2024
Cited by 1 | Viewed by 1168
Abstract
Phosphorus, an essential rare element in aquatic ecosystems, plays a key role in maintaining ecosystem balance. However, excess phosphorus leads to eutrophication and algal proliferation. To prevent eutrophication, the pretreatment and measuring of the concentration of total phosphorus (TP) is crucial. Compared to [...] Read more.
Phosphorus, an essential rare element in aquatic ecosystems, plays a key role in maintaining ecosystem balance. However, excess phosphorus leads to eutrophication and algal proliferation. To prevent eutrophication, the pretreatment and measuring of the concentration of total phosphorus (TP) is crucial. Compared to conventional TP pretreatment equipment (autoclave), a lab-on-a-chip detection device fabricated using micro-electromechanical system technology and titania (TiO2) as a photocatalyst is more convenient, efficient, and cost-effective. However, the wide bandgap of TiO2 (3.2 eV) limits photocatalytic activity. To address this problem, this paper describes the preparation of a TiO2/Au nanocomposite film using electron-beam evaporation and atomic-layer deposition, based on the introduction of gold film and TiO2 to a quartz substrate. The photocatalytic degradation properties of TiO2/Au nanocomposite films with thicknesses of 1, 2, 3, and 4 nm were assessed using rhodamine B as a pollutant. The experimental results demonstrate that the deposition of gold films with different thicknesses can enhance photocatalytic degradation efficiency through synergetic reactions in the charge separation process on the surface. The optimal photocatalytic efficiency is achieved when the deposition thickness is 2 nm, and it decreases with further increase in the thickness. When the photocatalytic reaction time is 15 min, the lab-on-a-chip (LOC) device with a 2-nm-thick gold layer and autoclave exhibits a similar TP pretreatment performance. Therefore, the proposed LOC device based on photocatalytic technology can address the limitations of conventional autoclave equipment, such as large volumes, long processing times, and high costs, thereby satisfying the growing demand for on-site evaluation. Full article
(This article belongs to the Topic Advanced Nanomaterials for Sensing Applications)
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14 pages, 2376 KiB  
Article
Exploring the Synergy between Nano-Formulated Linezolid and Polymyxin B as a Gram-Negative Effective Antibiotic Delivery System Based on Mesoporous Silica Nanoparticles
by Ismael Otri, Serena Medaglia, Ramón Martínez-Máñez, Elena Aznar and Félix Sancenón
Nanomaterials 2024, 14(2), 228; https://doi.org/10.3390/nano14020228 - 20 Jan 2024
Cited by 3 | Viewed by 1585
Abstract
Antimicrobial resistance is a current silent pandemic that needs new types of antimicrobial agents different from the classic antibiotics that are known to lose efficiency over time. Encapsulation of antibiotics inside nano-delivery systems could be a promising, effective strategy that is able to [...] Read more.
Antimicrobial resistance is a current silent pandemic that needs new types of antimicrobial agents different from the classic antibiotics that are known to lose efficiency over time. Encapsulation of antibiotics inside nano-delivery systems could be a promising, effective strategy that is able to delay the capability of pathogens to develop resistance mechanisms against antimicrobials. These systems can be adapted to deliver already discovered antibiotics to specific infection sites in a more successful way. Herein, mesoporous silica nanomaterials are used for an efficient delivery of a linezolid gram-positive antibiotic that acts synergistically with gram-negative antimicrobial polymyxin B. For this purpose, linezolid is encapsulated in the pores of the mesoporous silica, whose outer surface is coated with a polymyxin B membrane disruptor. The nanomaterial showed a good controlled-release performance in the presence of lipopolysaccharide, found in bacteria cell membranes, and the complete bacteria E. coli DH5α. The performed studies demonstrate that when the novel formulation is near bacteria, polymyxin B interacts with the cell membrane, thereby promoting its permeation. After this step, linezolid can easily penetrate the bacteria and act with efficacy to kill the microorganism. The nano-delivery system presents a highly increased antimicrobial efficacy against gram-negative bacteria, where the use of free linezolid is not effective, with a fractional inhibitory concentration index of 0.0063 for E. coli. Moreover, enhanced toxicity against gram-positive bacteria was confirmed thanks to the combination of both antibiotics in the same nanoparticles. Although this new nanomaterial should be further studied to reach clinical practice, the obtained results pave the way to the development of new nanoformulations which could help in the fight against bacterial infections. Full article
(This article belongs to the Topic Advanced Nanomaterials for Sensing Applications)
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16 pages, 13848 KiB  
Article
A Nanoporous Polymer Modified with Hexafluoroisopropanol to Detect Dimethyl Methylphosphonate
by Xuming Wang, Xin Li, Qiang Wu, Yubin Yuan, Weihua Liu, Chuanyu Han and Xiaoli Wang
Nanomaterials 2024, 14(1), 89; https://doi.org/10.3390/nano14010089 - 28 Dec 2023
Viewed by 1009
Abstract
The increasing threat of nerve agents has prompted the need for gas sensors with fast response, high sensitivity, and good stability. In this work, the hexafluoroisopropanol functional group was modified on a porous aromatic framework material, which served as a sensitive material for [...] Read more.
The increasing threat of nerve agents has prompted the need for gas sensors with fast response, high sensitivity, and good stability. In this work, the hexafluoroisopropanol functional group was modified on a porous aromatic framework material, which served as a sensitive material for detecting dimethyl methylphosphonate. A nerve agent sensor was made by coating sensitive materials on a surface acoustic wave device. Lots of pores in sensitive materials effectively increase the specific surface area and provide channels for diffusion of gas molecules. The introduction of hexafluoroisopropanols enables the sensor to specifically adsorb dimethyl methylphosphonate and improves the selectivity of the sensor. As a result, the developed gas sensor was able to detect dimethyl methylphosphonate at 0.8 ppm with response/recovery times of 29.8/43.8 s, and the detection limit of the gas sensor is about 0.11 ppm. The effects of temperature and humidity on the sensor were studied. The results show that the baseline of the sensor has a linear relationship with temperature and humidity, and the temperature and humidity have a significant effect on the response of the sensor. Furthermore, a device for real-time detection of nerve agent is reported. This work provides a new strategy for developing a gas sensor for detecting nerve agents. Full article
(This article belongs to the Topic Advanced Nanomaterials for Sensing Applications)
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11 pages, 2555 KiB  
Article
Printed Composite Film with Microporous/Micropyramid Hybrid Conductive Architecture for Multifunctional Flexible Force Sensors
by Yi-Fei Wang, Junya Yoshida, Yasunori Takeda, Ayako Yoshida, Takeru Kaneko, Tomohito Sekine, Daisuke Kumaki and Shizuo Tokito
Nanomaterials 2024, 14(1), 63; https://doi.org/10.3390/nano14010063 - 25 Dec 2023
Cited by 4 | Viewed by 1528
Abstract
Porous structures and micropatterning surfaces play a crucial role in the development of highly sensitive force sensors. However, achieving these two conductive architectures typically requires the synthesis of complex materials and expensive manufacturing processes. In this study, we introduce a novel conductive composite [...] Read more.
Porous structures and micropatterning surfaces play a crucial role in the development of highly sensitive force sensors. However, achieving these two conductive architectures typically requires the synthesis of complex materials and expensive manufacturing processes. In this study, we introduce a novel conductive composite film featuring a microporous/micropyramid hybrid conductive architecture, which is achieved through a straightforward process of materials mixing and one-step screen printing. By utilizing a deep eutectic solvent in the ink component, micropores are induced in the printed composite, while the mesh of the screen mask acts as a template, resulting in a micropyramid film surface. We have successfully realized highly sensitive flexible force sensors (0.15 kPa−1) with multifunctional capabilities for perceiving normal force and shear force. Full article
(This article belongs to the Topic Advanced Nanomaterials for Sensing Applications)
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10 pages, 1395 KiB  
Article
Spontaneous Synchronization of Two Bistable Pyridine-Furan Nanosprings Connected by an Oligomeric Bridge
by Anastasia A. Markina, Maria A. Frolkina, Alexander D. Muratov, Vladislav S. Petrovskii, Alexander F. Valov and Vladik A. Avetisov
Nanomaterials 2024, 14(1), 3; https://doi.org/10.3390/nano14010003 - 19 Dec 2023
Viewed by 873
Abstract
The intensive development of nanodevices acting as two-state systems has motivated the search for nanoscale molecular structures whose long-term conformational dynamics are similar to the dynamics of bistable mechanical systems such as Euler arches and Duffing oscillators. Collective synchrony in bistable dynamics of [...] Read more.
The intensive development of nanodevices acting as two-state systems has motivated the search for nanoscale molecular structures whose long-term conformational dynamics are similar to the dynamics of bistable mechanical systems such as Euler arches and Duffing oscillators. Collective synchrony in bistable dynamics of molecular-sized systems has attracted immense attention as a potential pathway to amplify the output signals of molecular nanodevices. Recently, pyridine-furan oligomers of helical shape that are a few nanometers in size and exhibit bistable dynamics similar to a Duffing oscillator have been identified through molecular dynamics simulations. In this article, we present the case of dynamical synchronization of these bistable systems. We show that two pyridine-furan springs connected by a rigid oligomeric bridge spontaneously synchronize vibrations and stochastic resonance enhances the synchronization effect. Full article
(This article belongs to the Topic Advanced Nanomaterials for Sensing Applications)
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17 pages, 1972 KiB  
Article
Ultrahighly Sensitive Surface-Enhanced Raman Spectroscopy Film of Silver Nanoparticles Dispersed in Three Dimensions on a Thin Alumina Nanowire Framework
by Myoung-Kyu Oh, Hyeonju Kim, Prince Gupta and Kyoungsik Kim
Nanomaterials 2023, 13(24), 3169; https://doi.org/10.3390/nano13243169 - 18 Dec 2023
Viewed by 1066
Abstract
To develop highly sensitive surface-enhanced Raman spectroscopy (SERS) films, various types of aggregated Ag nanowire (NW) and nanoparticle (NP) complex structures were fabricated using anodic aluminum oxide (AAO) templates and thermal evaporation. Aggregated AgNW structures with numerous tapered nanogaps were fabricated via Ag [...] Read more.
To develop highly sensitive surface-enhanced Raman spectroscopy (SERS) films, various types of aggregated Ag nanowire (NW) and nanoparticle (NP) complex structures were fabricated using anodic aluminum oxide (AAO) templates and thermal evaporation. Aggregated AgNW structures with numerous tapered nanogaps were fabricated via Ag deposition on aggregated thin alumina nanowires of different lengths. AgNP complex structures were obtained by collapsing vertically aligned thin alumina nanowires 1 μm in length and depositing AgNPs on their tops and sides using surface tension during ethanol drying after functionalization. The Raman signal enhancement factors (EFs) of the samples were evaluated by comparing the SERS signal of the thiophenol (TP) self-assembled monolayer (SAM) on the nanostructures with the Raman signal of neat TP. EFs as high as ~2.3 × 107 were obtained for the optimized aggregated AgNW structure (NW length of 1 μm) and ~3.5 × 107 for the optimized AgNP complex structure. The large EF of the AgNP complex film is attributed mainly to the AgNPs dispersed in three dimensions on the sides of the thin alumina nanowires, strongly implying some important, relevant physics yet to be discovered and also a very promising nanostructure scheme for developing ultrahighly sensitive SERS films with EF > 108. Full article
(This article belongs to the Topic Advanced Nanomaterials for Sensing Applications)
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73 pages, 7689 KiB  
Review
Wearable Nano-Based Gas Sensors for Environmental Monitoring and Encountered Challenges in Optimization
by Sara Hooshmand, Panagiotis Kassanos, Meysam Keshavarz, Pelin Duru, Cemre Irmak Kayalan, İzzet Kale and Mustafa Kemal Bayazit
Sensors 2023, 23(20), 8648; https://doi.org/10.3390/s23208648 - 23 Oct 2023
Cited by 20 | Viewed by 7618
Abstract
With a rising emphasis on public safety and quality of life, there is an urgent need to ensure optimal air quality, both indoors and outdoors. Detecting toxic gaseous compounds plays a pivotal role in shaping our sustainable future. This review aims to elucidate [...] Read more.
With a rising emphasis on public safety and quality of life, there is an urgent need to ensure optimal air quality, both indoors and outdoors. Detecting toxic gaseous compounds plays a pivotal role in shaping our sustainable future. This review aims to elucidate the advancements in smart wearable (nano)sensors for monitoring harmful gaseous pollutants, such as ammonia (NH3), nitric oxide (NO), nitrous oxide (N2O), nitrogen dioxide (NO2), carbon monoxide (CO), carbon dioxide (CO2), hydrogen sulfide (H2S), sulfur dioxide (SO2), ozone (O3), hydrocarbons (CxHy), and hydrogen fluoride (HF). Differentiating this review from its predecessors, we shed light on the challenges faced in enhancing sensor performance and offer a deep dive into the evolution of sensing materials, wearable substrates, electrodes, and types of sensors. Noteworthy materials for robust detection systems encompass 2D nanostructures, carbon nanomaterials, conducting polymers, nanohybrids, and metal oxide semiconductors. A dedicated section dissects the significance of circuit integration, miniaturization, real-time sensing, repeatability, reusability, power efficiency, gas-sensitive material deposition, selectivity, sensitivity, stability, and response/recovery time, pinpointing gaps in the current knowledge and offering avenues for further research. To conclude, we provide insights and suggestions for the prospective trajectory of smart wearable nanosensors in addressing the extant challenges. Full article
(This article belongs to the Topic Advanced Nanomaterials for Sensing Applications)
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22 pages, 8570 KiB  
Article
Exploration of the Different Dimensions of Wurtzite ZnO Structure Nanomaterials as Gas Sensors at Room Temperature
by Matshidiso P. Ramike, Patrick G. Ndungu and Messai A. Mamo
Nanomaterials 2023, 13(20), 2810; https://doi.org/10.3390/nano13202810 - 23 Oct 2023
Cited by 5 | Viewed by 1907
Abstract
In this work, we report on the synthesis of four morphologies of ZnO, namely, nanoparticles, nanorods, nanosheets, and nanoflowers, from a single precursor Zn(CH3COO)2·2H2O under different reaction conditions. The synthesised nanostructured materials were characterised using powder X-ray [...] Read more.
In this work, we report on the synthesis of four morphologies of ZnO, namely, nanoparticles, nanorods, nanosheets, and nanoflowers, from a single precursor Zn(CH3COO)2·2H2O under different reaction conditions. The synthesised nanostructured materials were characterised using powder X-ray diffraction (XRD), Fourier transform infrared (FTIR) and Raman spectroscopy, UV–Vis, XPS analysis, transmission electron microscopy (TEM), scanning electron microscopy (SEM), and nitrogen sorption at 77 K. The XRD, FTIR, and Raman analyses did not reveal any significant differences among the nanostructures, but differences in the electronic properties were noted among the different morphologies. The TEM and SEM analyses confirmed the four different morphologies of the ZnO nanostructures. The textural characteristics revealed that the specific surface areas were different, being 1.3, 6.7, 12.7, and 26.8 m2/g for the nanoflowers, nanoparticles, nanorods, and nanosheets, respectively. The ZnO nanostructures were then mixed with carbon nanoparticles (CNPs) and cellulose acetate (CA) to make nanocomposites that were then used as sensing materials in solid-state sensors to detect methanol, ethanol, and isopropanol vapour at room temperature. The sensors’ responses were recorded in relative resistance. When detecting methanol, 6 out of 12 sensors were responsive, and the most sensitive sensor was the composite with a mass ratio of 1:1:1 of ZnO nanorods:CNPs:CA with a sensitivity of 0.7740 Ω ppm−1. Regarding the detection of ethanol vapour, 9 of the 12 sensors were responsive, and the 3:1:1 mass ratio with ZnO nanoparticles was the most sensitive at 4.3204 Ω ppm−1. Meanwhile, with isopropanol, 5 out of the 12 sensors were active and, with a sensitivity of 3.4539 Ω ppm−1, the ZnO nanoparticles in a 3:1:1 mass ratio were the most sensitive. Overall, the response of the sensors depended on the morphology of the nanostructured ZnO materials, the mass ratio of the sensing materials in the composites, and the type of analyte. The sensing mechanism was governed by the surface reaction on the sensing materials rather than pores hindering the analyte molecules from reaching the active site, since the pore size is larger than the kinetic diameter of the analyte molecules. Generally, the sensors responded well to the ethanol analyte, rather than methanol and isopropanol. This is due to ethanol molecules displaying a more enhanced electron-donating ability. Full article
(This article belongs to the Topic Advanced Nanomaterials for Sensing Applications)
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16 pages, 4794 KiB  
Article
Hybrid Pressure Sensor Based on Carbon Nano-Onions and Hierarchical Microstructures with Synergistic Enhancement Mechanism for Multi-Parameter Sleep Monitoring
by Jie Zou, Yina Qiao, Juanhong Zhao, Zhigang Duan, Junbin Yu, Yu Jing, Jian He, Le Zhang, Xiujian Chou and Jiliang Mu
Nanomaterials 2023, 13(19), 2692; https://doi.org/10.3390/nano13192692 - 1 Oct 2023
Cited by 3 | Viewed by 1518
Abstract
With the existing pressure sensors, it is difficult to achieve the unification of wide pressure response range and high sensitivity. Furthermore, the preparation of pressure sensors with excellent performance for sleep health monitoring has become a research difficulty. In this paper, based on [...] Read more.
With the existing pressure sensors, it is difficult to achieve the unification of wide pressure response range and high sensitivity. Furthermore, the preparation of pressure sensors with excellent performance for sleep health monitoring has become a research difficulty. In this paper, based on material and microstructure synergistic enhancement mechanism, a hybrid pressure sensor (HPS) integrating triboelectric pressure sensor (TPS) and piezoelectric pressure sensor (PPS) is proposed. For the TPS, a simple, low-cost, and structurally controllable microstructure preparation method is proposed in order to investigate the effect of carbon nano-onions (CNOs) and hierarchical composite microstructures on the electrical properties of CNOs@Ecoflex. The PPS is used to broaden the pressure response range and reduce the pressure detection limit of HPS. It has been experimentally demonstrated that the HPS has a high sensitivity of 2.46 V/104 Pa (50–600 kPa) and a wide response range of up to 1200 kPa. Moreover, the HPS has a low detection limit (10 kPa), a high stability (over 100,000 cycles), and a fast response time. The sleep monitoring system constructed based on HPS shows remarkable performance in breathing state recognition and sleeping posture supervisory control, which will exhibit enormous potential in areas such as sleep health monitoring and potential disease prediction. Full article
(This article belongs to the Topic Advanced Nanomaterials for Sensing Applications)
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15 pages, 3971 KiB  
Article
Hybrid Nanoparticle/DNAzyme Electrochemical Biosensor for the Detection of Divalent Heavy Metal Ions and Cr3+
by Evangelos Skotadis, Evangelos Aslanidis, Georgios Tsekenis, Chrysi Panagopoulou, Annita Rapesi, Georgia Tzourmana, Stella Kennou, Spyridon Ladas, Angelos Zeniou and Dimitris Tsoukalas
Sensors 2023, 23(18), 7818; https://doi.org/10.3390/s23187818 - 12 Sep 2023
Cited by 4 | Viewed by 2067
Abstract
A hybrid noble nanoparticle/DNAzyme electrochemical biosensor is proposed for the detection of Pb2+, Cd2+, and Cr3+. The sensor takes advantage of a well-studied material that is known for its selective interaction with heavy metal ions (i.e., DNAzymes), [...] Read more.
A hybrid noble nanoparticle/DNAzyme electrochemical biosensor is proposed for the detection of Pb2+, Cd2+, and Cr3+. The sensor takes advantage of a well-studied material that is known for its selective interaction with heavy metal ions (i.e., DNAzymes), which is combined with metallic nanoparticles. The double-helix structure of DNAzymes is known to dissociate into smaller fragments in the presence of specific heavy metal ions; this results in a measurable change in device resistance due to the collapse of conductive inter-nanoparticle DNAzyme bridging. The paper discusses the effect of DNAzyme anchoring groups (i.e., thiol and amino functionalization groups) on device performance and reports on the successful detection of all three target ions in concentrations that are well below their maximum permitted levels in tap water. While the use of DNAzymes for the detection of lead in particular and, to some extent, cadmium has been studied extensively, this is one of the few reports on the successful detection of chromium (III) via a sensor incorporating DNAzymes. The sensor showed great potential for its future integration in autonomous and remote sensing systems due to its low power characteristics, simple and cost-effective fabrication, and easy automation and measurement. Full article
(This article belongs to the Topic Advanced Nanomaterials for Sensing Applications)
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14 pages, 8252 KiB  
Article
Ag-Doped MoSe2/ZnO Heterojunctions: A Highly Responsive Gas-Sensitive Material for Selective Detection of NO Based on DFT Study
by Tao He, Hongcheng Liu, Jing Zhang, Yuepeng Yang, Yuxiao Jiang, Ying Zhang, Jiaqi Feng and Kelin Hu
Nanomaterials 2023, 13(18), 2510; https://doi.org/10.3390/nano13182510 - 7 Sep 2023
Cited by 5 | Viewed by 1557
Abstract
In this work, the adsorption and sensing behavior of Ag-doped MoSe2/ZnO heterojunctions for H2, CH4, CO2, NO, CO, and C2H4 have been studied based on density functional theory (DFT). In gas adsorption [...] Read more.
In this work, the adsorption and sensing behavior of Ag-doped MoSe2/ZnO heterojunctions for H2, CH4, CO2, NO, CO, and C2H4 have been studied based on density functional theory (DFT). In gas adsorption analysis, the adsorption energy, adsorption distance, transfer charge, total electron density, density of states (DOS), energy band structure, frontier molecular orbital, and work function (WF) of each gas has been calculated. Furthermore, the reusability and stability of the Ag-doped MoSe2/ZnO heterojunctions have also been studied. The results showed that Ag-doped MoSe2/ZnO heterojunctions have great potential to be a candidate of highly selective and responsive gas sensors for NO detection with excellent reusability and stability. Full article
(This article belongs to the Topic Advanced Nanomaterials for Sensing Applications)
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14 pages, 2079 KiB  
Article
Electrochemical Detection of SARS-CoV-2 Using Immunomagnetic Separation and Gold Nanoparticles on Unmodified Screen-Printed Carbon Electrodes
by Christopher J. Lambert, Harikrishnan Jayamohan, Bruce K. Gale, Lars B. Laurentius, Dhruv Patel, Madison Hansen, Tawsif Mahmood and Himanshu Jayant Sant
Appl. Sci. 2023, 13(18), 10007; https://doi.org/10.3390/app131810007 - 5 Sep 2023
Cited by 1 | Viewed by 1533
Abstract
The COVID-19 pandemic has underscored the critical need for virus detection methods that are precise, simple, quick, and cost-effective. Electrochemical immunoassay-based methods are a practical solution given their ability to quickly, inexpensively, sensitively, and selectively detect the virus at the point of care. [...] Read more.
The COVID-19 pandemic has underscored the critical need for virus detection methods that are precise, simple, quick, and cost-effective. Electrochemical immunoassay-based methods are a practical solution given their ability to quickly, inexpensively, sensitively, and selectively detect the virus at the point of care. This study details the immunomagnetic capture of SARS-CoV-2 nucleocapsid protein in nasal samples, followed by electrochemical detection using gold nanoparticle labels on a screen-printed carbon electrode. We determined ideal conditions for the size of the gold nanoparticles and the length of the deposition time to maximize the electrochemical signal. The limit of detection for nucleocapsid protein was determined to be 2.64 ng/mL in PBS. The assay was successfully demonstrated to detect nucleocapsid protein in SARS-CoV-2-positive samples with a viral load as low as Ct = 25 (p-value < 0.0001 vs. negative patient control). Full article
(This article belongs to the Topic Advanced Nanomaterials for Sensing Applications)
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18 pages, 11547 KiB  
Article
Effect of Hydrogen Plasma Treatment on the Sensitivity of ZnO Based Electrochemical Non-Enzymatic Biosensor
by Diana B. Tolubayeva, Lesya V. Gritsenko, Yevgeniya Y. Kedruk, Madi B. Aitzhanov, Renata R. Nemkayeva and Khabibulla A. Abdullin
Biosensors 2023, 13(8), 793; https://doi.org/10.3390/bios13080793 - 7 Aug 2023
Cited by 4 | Viewed by 1557
Abstract
Information on vitamin C—ascorbic acid (AA)—content is important as it facilitates the provision of dietary advice and strategies for the prevention and treatment of conditions associated with AA deficiency or excess. The methods of determining AA content include chromatographic techniques, spectrophotometry, and electrochemical [...] Read more.
Information on vitamin C—ascorbic acid (AA)—content is important as it facilitates the provision of dietary advice and strategies for the prevention and treatment of conditions associated with AA deficiency or excess. The methods of determining AA content include chromatographic techniques, spectrophotometry, and electrochemical methods of analysis. In the present work, an electrochemical enzyme-free ascorbic acid sensor for a neutral medium has been developed. The sensor is based on zinc oxide nanowire (ZnO NW) arrays synthesized via low-temperature chemical deposition (Chemical Bath Deposition) on the surface of an ITO substrate. The sensitivity of the electrochemical enzyme-free sensor was found to be dependent on the process treatments. The AA sensitivity values measured in a neutral PBS electrolyte were found to be 73, 44, and 92 µA mM−1 cm−2 for the ZnO NW-based sensors of the pristine, air-annealed (AT), and air-annealed followed by hydrogen plasma treatment (AT+PT), respectively. The simple H-plasma treatment of ZnO nanowire arrays synthesized via low-temperature chemical deposition has been shown to be an effective process step to produce an enzyme-free sensor for biological molecules in a neutral electrolyte for applications in health care and biomedical safety. Full article
(This article belongs to the Topic Advanced Nanomaterials for Sensing Applications)
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14 pages, 7539 KiB  
Article
Conductometric Gas Sensor Based on MoO3 Nanoribbon Modified with rGO Nanosheets for Ethylenediamine Detection at Room Temperature
by Hongda Liu, Jiongjiang Liu, Qi Liu, Yinghui Li, Guo Zhang and Chunying He
Nanomaterials 2023, 13(15), 2220; https://doi.org/10.3390/nano13152220 - 31 Jul 2023
Cited by 4 | Viewed by 1837
Abstract
An ethylenediamine (EDA) gas sensor based on a composite of MoO3 nanoribbon and reduced graphene oxide (rGO) was fabricated in this work. MoO3 nanoribbon/rGO composites were synthesized using a hydrothermal process. The crystal structure, morphology, and elemental composition of MoO3 [...] Read more.
An ethylenediamine (EDA) gas sensor based on a composite of MoO3 nanoribbon and reduced graphene oxide (rGO) was fabricated in this work. MoO3 nanoribbon/rGO composites were synthesized using a hydrothermal process. The crystal structure, morphology, and elemental composition of MoO3/rGO were analyzed via XRD, FT-IR, Raman, TEM, SEM, XPS, and EPR characterization. The response value of MoO3/rGO to 100 ppm ethylenediamine was 843.7 at room temperature, 1.9 times higher than that of MoO3 nanoribbons. The MoO3/rGO sensor has a low detection limit (LOD) of 0.235 ppm, short response time (8 s), good selectivity, and long-term stability. The improved gas-sensitive performance of MoO3/rGO composites is mainly due to the excellent electron transport properties of graphene, the generation of heterojunctions, the higher content of oxygen vacancies, and the large specific surface area in the composites. This study presents a new approach to efficiently and selectively detect ethylenediamine vapor with low power. Full article
(This article belongs to the Topic Advanced Nanomaterials for Sensing Applications)
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13 pages, 3373 KiB  
Article
Solution-Grown MAPbBr3 Single Crystals for Self-Powered Detection of X-rays with High Energies above One Megaelectron Volt
by Beomjun Park, Juyoung Ko, Jangwon Byun, Sandeep Pandey, Byungdo Park, Jeongho Kim and Man-Jong Lee
Nanomaterials 2023, 13(15), 2157; https://doi.org/10.3390/nano13152157 - 25 Jul 2023
Cited by 5 | Viewed by 1930
Abstract
Perovskite single crystals are actively studied as X-ray detection materials with enhanced sensitivity. Moreover, the feasibility of using perovskites for self-powered devices such as photodetectors, UV detectors, and X-ray detectors can significantly expand their application range. In this work, the charge carrier transport [...] Read more.
Perovskite single crystals are actively studied as X-ray detection materials with enhanced sensitivity. Moreover, the feasibility of using perovskites for self-powered devices such as photodetectors, UV detectors, and X-ray detectors can significantly expand their application range. In this work, the charge carrier transport and photocurrent properties of MAPbBr3 single crystals (MSCs) are improved by the mechanochemical surface treatment using glycerin combined with an additional electrode design that forms an ohmic contact. The sensitivity of MSC-based detectors and pulse shape generated by X-rays are enhanced at various bias voltages. The synthesized MSC detectors generate direction-dependent photocurrents, which indicate the presence of a polarization-induced internal electric field. In addition, photocurrent signals are produced by X-rays with energies greater than 1 MeV under a zero-bias voltage. This work demonstrates a high application potential of perovskites as self-powered detectors for X-rays with energies exceeding 1 MeV. Full article
(This article belongs to the Topic Advanced Nanomaterials for Sensing Applications)
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26 pages, 7482 KiB  
Review
Electrochemiluminescence of Semiconductor Quantum Dots and Its Biosensing Applications: A Comprehensive Review
by Hui Sun, Ping Zhou and Bin Su
Biosensors 2023, 13(7), 708; https://doi.org/10.3390/bios13070708 - 5 Jul 2023
Cited by 7 | Viewed by 3232
Abstract
Electrochemiluminescence (ECL) is the chemiluminescence triggered by electrochemical reactions. Due to the unique excitation mode and inherent low background, ECL has been a powerful analytical technique to be widely used in biosensing and imaging. As an emerging ECL luminophore, semiconductor quantum dots (QDs) [...] Read more.
Electrochemiluminescence (ECL) is the chemiluminescence triggered by electrochemical reactions. Due to the unique excitation mode and inherent low background, ECL has been a powerful analytical technique to be widely used in biosensing and imaging. As an emerging ECL luminophore, semiconductor quantum dots (QDs) have apparent advantages over traditional molecular luminophores in terms of luminescence efficiency and signal modulation ability. Therefore, the development of an efficient ECL system with QDs as luminophores is of great significance to improve the sensitivity and detection flux of ECL biosensors. In this review, we give a comprehensive summary of recent advances in ECL using semiconductor QDs as luminophores. The luminescence process and ECL mechanism of semiconductor QDs with various coreactants are discussed first. Specifically, the influence of surface defects on ECL performance of semiconductor QDs is emphasized and several typical ECL enhancement strategies are summarized. Then, the applications of semiconductor QDs in ECL biosensing are overviewed, including immunoassay, nucleic acid analysis and the detection of small molecules. Finally, the challenges and prospects of semiconductor QDs as ECL luminophores in biosensing are featured. Full article
(This article belongs to the Topic Advanced Nanomaterials for Sensing Applications)
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18 pages, 14778 KiB  
Article
Nanocomposite Co3O4-ZnO Thin Films for Photoconductivity Sensors
by Victor V. Petrov, Victor V. Sysoev, Irina O. Ignatieva, Irina A. Gulyaeva, Maria G. Volkova, Alexandra P. Ivanishcheva, Soslan A. Khubezhov, Yuri N. Varzarev and Ekaterina M. Bayan
Sensors 2023, 23(12), 5617; https://doi.org/10.3390/s23125617 - 15 Jun 2023
Cited by 7 | Viewed by 1616
Abstract
Thin nanocomposite films based on zinc oxide (ZnO) added with cobalt oxide (Co3O4) were synthesized by solid-phase pyrolysis. According to XRD, the films consist of a ZnO wurtzite phase and a cubic structure of Co3O4 spinel. [...] Read more.
Thin nanocomposite films based on zinc oxide (ZnO) added with cobalt oxide (Co3O4) were synthesized by solid-phase pyrolysis. According to XRD, the films consist of a ZnO wurtzite phase and a cubic structure of Co3O4 spinel. The crystallite sizes in the films increased from 18 nm to 24 nm with growing annealing temperature and Co3O4 concentration. Optical and X-ray photoelectron spectroscopy data revealed that enhancing the Co3O4 concentration leads to a change in the optical absorption spectrum and the appearance of allowed transitions in the material. Electrophysical measurements showed that Co3O4-ZnO films have a resistivity up to 3 × 104 Ohm∙cm and a semiconductor conductivity close to intrinsic. With advancing the Co3O4 concentration, the mobility of the charge carriers was found to increase by almost four times. The photosensors based on the 10Co-90Zn film exhibited a maximum normalized photoresponse when exposed to radiation with wavelengths of 400 nm and 660 nm. It was found that the same film has a minimum response time of ca. 26.2 ms upon exposure to radiation of 660 nm wavelength. The photosensors based on the 3Co-97Zn film have a minimum response time of ca. 58.3 ms versus the radiation of 400 nm wavelength. Thus, the Co3O4 content was found to be an effective impurity to tune the photosensitivity of radiation sensors based on Co3O4-ZnO films in the wavelength range of 400–660 nm. Full article
(This article belongs to the Topic Advanced Nanomaterials for Sensing Applications)
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13 pages, 3544 KiB  
Article
Thermal Stability and Melting Dynamics of Bimetallic Au@Pt@Au Core-Shell Nanoparticles
by Vadym Borysiuk, Iakov A. Lyashenko and Valentin L. Popov
Sensors 2023, 23(12), 5478; https://doi.org/10.3390/s23125478 - 10 Jun 2023
Cited by 2 | Viewed by 1572
Abstract
Thermal stability is an important feature of the materials used as components and parts of sensors and other devices of nanoelectronics. Here we report the results of the computational study of the thermal stability of the triple layered Au@Pt@Au core-shell nanoparticles, which are [...] Read more.
Thermal stability is an important feature of the materials used as components and parts of sensors and other devices of nanoelectronics. Here we report the results of the computational study of the thermal stability of the triple layered Au@Pt@Au core-shell nanoparticles, which are promising materials for H2O2 bi-directional sensing. A distinct feature of the considered sample is the raspberry-like shape, due to the presence of Au nanoprotuberances on its surface. The thermal stability and melting of the samples were studied within classical molecular dynamics simulations. Interatomic forces were computed within the embedded atom method. To investigate the thermal properties of Au@Pt@Au nanoparticles, structural parameters such as Lindemann indexes, radial distribution functions, linear distributions of concentration, and atomistic configurations were calculated. As the performed simulations showed, the raspberry-like structure of the nanoparticle was preserved up to approximately 600 K, while the general core-shell structure was maintained up to approximately 900 K. At higher temperatures, the destruction of the initial fcc crystal structure and core-shell composition was observed for both considered samples. As Au@Pt@Au nanoparticles demonstrated high sensing performance due to their unique structure, the obtained results may be useful for the further design and fabrication of the nanoelectronic devices that are required to work within a certain range of temperatures. Full article
(This article belongs to the Topic Advanced Nanomaterials for Sensing Applications)
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14 pages, 6114 KiB  
Article
A Label-Free Carbohydrate-Based Electrochemical Sensor to Detect Escherichia coli Pathogenic Bacteria Using D-mannose on a Glassy Carbon Electrode
by Sakineh Hargol Zadeh, Soheila Kashanian and Maryam Nazari
Biosensors 2023, 13(6), 619; https://doi.org/10.3390/bios13060619 - 5 Jun 2023
Cited by 5 | Viewed by 2183
Abstract
Controlling water and food contamination by pathogenic organisms requires quick, simple, and low-cost methods. Using the affinity between mannose and type I fimbriae in the cell wall of Escherichia coli (E. coli) bacteria as evaluation elements compared to the conventional plate [...] Read more.
Controlling water and food contamination by pathogenic organisms requires quick, simple, and low-cost methods. Using the affinity between mannose and type I fimbriae in the cell wall of Escherichia coli (E. coli) bacteria as evaluation elements compared to the conventional plate counting technique enables a reliable sensing platform for the detection of bacteria. In this study, a simple new sensor was developed based on electrochemical impedance spectroscopy (EIS) for rapid and sensitive detection of E. coli. The biorecogniton layer of the sensor was formed by covalent attachment of p-carboxyphenylamino mannose (PCAM) to gold nanoparticles (AuNPs) electrodeposited on the surface of a glassy carbon electrode (GCE). The resultant structure of PCAM was characterized and confirmed using a Fourier Transform Infrared Spectrometer (FTIR). The developed biosensor demonstrated a linear response with a logarithm of bacterial concentration (R2 = 0.998) in the range of 1.3 × 10 1~1.3 × 106 CFU·mL−1 with the limit of detection of 2 CFU·mL−1 within 60 min. The sensor did not generate any significant signals with two non-target strains, demonstrating the high selectivity of the developed biorecognition chemistry. The selectivity of the sensor and its applicability to analysis of the real samples were investigated in tap water and low-fat milk samples. Overall, the developed sensor showed to be promising for the detection of E. coli pathogens in water and low-fat milk due to its high sensitivity, short detection time, low cost, high specificity, and user-friendliness. Full article
(This article belongs to the Topic Advanced Nanomaterials for Sensing Applications)
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30 pages, 3770 KiB  
Review
Development of Two-Dimensional Functional Nanomaterials for Biosensor Applications: Opportunities, Challenges, and Future Prospects
by Shamsa Kizhepat, Akash S. Rasal, Jia-Yaw Chang and Hui-Fen Wu
Nanomaterials 2023, 13(9), 1520; https://doi.org/10.3390/nano13091520 - 29 Apr 2023
Cited by 16 | Viewed by 3655
Abstract
New possibilities for the development of biosensors that are ready to be implemented in the field have emerged thanks to the recent progress of functional nanomaterials and the careful engineering of nanostructures. Two-dimensional (2D) nanomaterials have exceptional physical, chemical, highly anisotropic, chemically active, [...] Read more.
New possibilities for the development of biosensors that are ready to be implemented in the field have emerged thanks to the recent progress of functional nanomaterials and the careful engineering of nanostructures. Two-dimensional (2D) nanomaterials have exceptional physical, chemical, highly anisotropic, chemically active, and mechanical capabilities due to their ultra-thin structures. The diversity of the high surface area, layered topologies, and porosity found in 2D nanomaterials makes them amenable to being engineered with surface characteristics that make it possible for targeted identification. By integrating the distinctive features of several varieties of nanostructures and employing them as scaffolds for bimolecular assemblies, biosensing platforms with improved reliability, selectivity, and sensitivity for the identification of a plethora of analytes can be developed. In this review, we compile a number of approaches to using 2D nanomaterials for biomolecule detection. Subsequently, we summarize the advantages and disadvantages of using 2D nanomaterials in biosensing. Finally, both the opportunities and the challenges that exist within this potentially fruitful subject are discussed. This review will assist readers in understanding the synthesis of 2D nanomaterials, their alteration by enzymes and composite materials, and the implementation of 2D material-based biosensors for efficient bioanalysis and disease diagnosis. Full article
(This article belongs to the Topic Advanced Nanomaterials for Sensing Applications)
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14 pages, 2995 KiB  
Review
A Minireview for Recent Development of Nanomaterial-Based Detection of Antibiotics
by Jiafu Hong, Mengxing Su, Kunmeng Zhao, Yihui Zhou, Jingjing Wang, Shu-Feng Zhou and Xuexia Lin
Biosensors 2023, 13(3), 327; https://doi.org/10.3390/bios13030327 - 27 Feb 2023
Cited by 17 | Viewed by 3357
Abstract
Antibiotics are considered a new type of organic pollutant. Antibiotic residues have become a global issue due to their harm to human health. As the use of antibiotics is increasing in human life, such as in medicine, crops, livestock, and even drinking water, [...] Read more.
Antibiotics are considered a new type of organic pollutant. Antibiotic residues have become a global issue due to their harm to human health. As the use of antibiotics is increasing in human life, such as in medicine, crops, livestock, and even drinking water, the accurate analysis of antibiotics is very vital. In order to develop rapid and on-site approaches for the detection of antibiotics and the analysis of trace-level residual antibiotics, a high-sensitivity, simple, and portable solution is required. Meanwhile, the rapid nanotechnology development of a variety of nanomaterials has been achieved. In this review, nanomaterial-based techniques for antibiotic detection are discussed, and some reports that have employed combined nanomaterials with optical techniques or electrochemical techniques are highlighted. Full article
(This article belongs to the Topic Advanced Nanomaterials for Sensing Applications)
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15 pages, 6601 KiB  
Article
Influences of CNT Dispersion Methods, W/C Ratios, and Concrete Constituents on Piezoelectric Properties of CNT-Modified Smart Cementitious Materials
by Tofatun Jannat, Ying Huang, Zhi Zhou and Dawei Zhang
Sensors 2023, 23(5), 2602; https://doi.org/10.3390/s23052602 - 27 Feb 2023
Cited by 2 | Viewed by 2219
Abstract
In order to achieve effective monitoring of concrete structures for sound structural health, the addition of carbon nanotubes (CNTs) into cementitious materials offers a promising solution for fabricating CNT-modified smart concrete with self-sensing ability. This study investigated the influences of CNT dispersion method, [...] Read more.
In order to achieve effective monitoring of concrete structures for sound structural health, the addition of carbon nanotubes (CNTs) into cementitious materials offers a promising solution for fabricating CNT-modified smart concrete with self-sensing ability. This study investigated the influences of CNT dispersion method, water/cement (W/C) ratio, and concrete constituents on the piezoelectric properties of CNT-modified cementitious materials. Three CNT dispersion methods (direct mixing, sodium dodecyl benzenesulfonate (NaDDBS) and carboxymethyl cellulose (CMC) surface treatment), three W/C ratios (0.4, 0.5, and 0.6), and three concrete constituent compositions (pure cement, cement/sand, and cement/sand/coarse aggregate) were considered. The experimental results showed that CNT-modified cementitious materials with CMC surface treatment had valid and consistent piezoelectric responses to external loading. The piezoelectric sensitivity improved significantly with increased W/C ratio and reduced progressively with the addition of sand and coarse aggregates. Full article
(This article belongs to the Topic Advanced Nanomaterials for Sensing Applications)
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12 pages, 2347 KiB  
Article
Monitoring Water Absorption and Desorption in Untreated and Consolidated Tuff by a Non-Invasive Graphene-Based Humidity Sensor
by Federico Olivieri, Rachele Castaldo, Gennaro Gentile and Marino Lavorgna
Materials 2023, 16(5), 1878; https://doi.org/10.3390/ma16051878 - 24 Feb 2023
Cited by 1 | Viewed by 1418
Abstract
A hybrid montmorillonite (MMT)/reduced graphene oxide (rGO) film was realised and used as a non-invasive sensor for the monitoring of water absorption and desorption in pristine and consolidated tuff stones. This film was obtained by casting from a water dispersion containing graphene oxide [...] Read more.
A hybrid montmorillonite (MMT)/reduced graphene oxide (rGO) film was realised and used as a non-invasive sensor for the monitoring of water absorption and desorption in pristine and consolidated tuff stones. This film was obtained by casting from a water dispersion containing graphene oxide (GO), montmorillonite and ascorbic acid; then the GO component was thermo-chemically reduced and the ascorbic acid phase was removed by washing. The hybrid film showed electrical surface conductivity that varied linearly with the relative humidity, ranging from 2.3 × 10−3 S in dry conditions to 5.0 × 10−3 S at 100% RH. The sensor was applied onto tuff stone samples through the use of a high amorphous polyvinyl alcohol layer (HAVOH) adhesive, which guaranteed good water diffusion from the stone to the film and was tested during water capillary absorption and drying tests. Results show that the sensor is able to monitor water content changes in the stone, being potentially useful to evaluate the water absorption and desorption behaviour of porous samples both in laboratory environments and in situ. Full article
(This article belongs to the Topic Advanced Nanomaterials for Sensing Applications)
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14 pages, 2480 KiB  
Article
CDs-Peroxyfluor Conjugation for Ratiometric Fluorescence Detection of Glucose and Shortening Its Detection Time from Reaction Dynamic Perspective
by Yangjie Li, Site Luo, Xin Wang, Yang He and Haihu Yu
Biosensors 2023, 13(2), 222; https://doi.org/10.3390/bios13020222 - 3 Feb 2023
Viewed by 1757
Abstract
A ratiometric fluorescence probe based on the conjugation of peroxyfluor-NHS (PF) and carbon dots (CDs) was designed for selective and rapid detection of glucose. When glucose was catalytically oxidized by glucose oxidase (GOx), the product H2O2 would react with colorless [...] Read more.
A ratiometric fluorescence probe based on the conjugation of peroxyfluor-NHS (PF) and carbon dots (CDs) was designed for selective and rapid detection of glucose. When glucose was catalytically oxidized by glucose oxidase (GOx), the product H2O2 would react with colorless and non-fluorescent peroxyfluor moiety to give the colored and fluorescent fluorescein moiety which would absorb the energy of CDs emission at 450 nm due to the Förster Resonance Energy Transfer (FRET) and generate a new emission peak at 517 nm. The reaction between PF and H2O2 was slow with a rate constant of about 2.7 × 10−4 s−1 under pseudo-first-order conditions (1 uM PF, 1 mM H2O2), which was unconducive to rapid detection. Given this, a short time detection method was proposed by studying the kinetics of the reaction between PF and H2O2. In this method, the detection time was fixed at three minutes. The linear detection of glucose could be well realized even if the reaction was partially done. As glucose concentration increased from 0.05 mM to 5 mM, the fluorescence intensity ratio (I517/I450) after 3 minutes’ reaction of CDs-PF and glucose oxidation products changed linearly from 0.269 to 1.127 with the limit of detection (LOD) of 17.19 μM. In addition, the applicability of the probe in blood glucose detection was verified. Full article
(This article belongs to the Topic Advanced Nanomaterials for Sensing Applications)
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12 pages, 3860 KiB  
Article
High-Sensitivity Sensing in All-Dielectric Metasurface Driven by Quasi-Bound States in the Continuum
by Zhao Jing, Wang Jiaxian, Gao Lizhen and Qiu Weibin
Nanomaterials 2023, 13(3), 505; https://doi.org/10.3390/nano13030505 - 27 Jan 2023
Cited by 18 | Viewed by 3602
Abstract
Quasi-bound states in the continuum (quasi-BIC) in all-dielectric metasurfaces provide a crucial platform for sensing due to its ability to enhance strong matter interactions between light-waves and analytes. In this study, a novel high-sensitivity all-dielectric sensor composed of a periodic array of silicon [...] Read more.
Quasi-bound states in the continuum (quasi-BIC) in all-dielectric metasurfaces provide a crucial platform for sensing due to its ability to enhance strong matter interactions between light-waves and analytes. In this study, a novel high-sensitivity all-dielectric sensor composed of a periodic array of silicon (Si) plates with square nanoholes in the continuous near-infrared band is theoretically proposed. By adjusting the position of the square nanohole, the symmetry-protected BIC and Friedrich–Wintgen BIC (FW–BIC) can be excited. The torodial dipole (TD) and electric quadruple (EQ) are demonstrated to play a dominating role in the resonant modes by near-field analysis and multipole decomposition. The results show that the sensitivity, the Q-factor, and the corresponding figure of merit (FOM) can simultaneously reach 399 nm/RIU (RIU is refractive index unit), 4959, and 1281, respectively. Compared with other complex nanostructures, the proposed metasurface is more feasible and practical, which may open up an avenue for the development of ultrasensitive sensors. Full article
(This article belongs to the Topic Advanced Nanomaterials for Sensing Applications)
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21 pages, 5915 KiB  
Article
Modeling and Optimization of Sensitivity and Creep for Multi-Component Sensing Materials
by Gangping Bi, Bowen Xiao, Yuanchang Lin, Shaoqiu Yan, Ying Tang, Songxiying He, Mingsheng Shang and Guotian He
Nanomaterials 2023, 13(2), 298; https://doi.org/10.3390/nano13020298 - 11 Jan 2023
Viewed by 1648
Abstract
Pressure sensors urgently need high-performance sensing materials in order to be developed further. Sensitivity and creep are regarded as two key indices for assessing a sensor’s performance. For the design and optimization of sensing materials, an accurate estimation of the impact of several [...] Read more.
Pressure sensors urgently need high-performance sensing materials in order to be developed further. Sensitivity and creep are regarded as two key indices for assessing a sensor’s performance. For the design and optimization of sensing materials, an accurate estimation of the impact of several parameters on sensitivity and creep is essential. In this study, sensitivity and creep were predicted using the response surface methodology (RSM) and support vector regression (SVR), respectively. The input parameters were the concentrations of nickel (Ni) particles, multiwalled carbon nanotubes (MWCNTs), and multilayer graphene (MLG), as well as the magnetic field intensity (B). According to statistical measures, the SVR model exhibited a greater level of predictability and accuracy. The non-dominated sorting genetic-II algorithm (NSGA-II) was used to generate the Pareto-optimal fronts, and decision-making was used to determine the final optimal solution. With these conditions, the optimized results revealed an improved performance compared to the earlier study, with an average sensitivity of 0.059 kPa−1 in the pressure range of 0–16 kPa and a creep of 0.0325, which showed better sensitivity in a wider range compared to previous work. The theoretical sensitivity and creep were relatively similar to the actual values, with relative deviations of 0.317% and 0.307% after simulation and experimental verification. Future research for transducer performance optimization can make use of the provided methodology because it is representative. Full article
(This article belongs to the Topic Advanced Nanomaterials for Sensing Applications)
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18 pages, 2444 KiB  
Review
An Overview of Flexible Sensors: Development, Application, and Challenges
by Enze Liu, Zhimin Cai, Yawei Ye, Mingyue Zhou, Hui Liao and Ying Yi
Sensors 2023, 23(2), 817; https://doi.org/10.3390/s23020817 - 10 Jan 2023
Cited by 29 | Viewed by 6594
Abstract
The emergence and advancement of flexible electronics have great potential to lead development trends in many fields, such as “smart electronic skin” and wearable electronics. By acting as intermediates to detect a variety of external stimuli or physiological parameters, flexible sensors are regarded [...] Read more.
The emergence and advancement of flexible electronics have great potential to lead development trends in many fields, such as “smart electronic skin” and wearable electronics. By acting as intermediates to detect a variety of external stimuli or physiological parameters, flexible sensors are regarded as a core component of flexible electronic systems and have been extensively studied. Unlike conventional rigid sensors requiring costly instruments and complicated fabrication processes, flexible sensors can be manufactured by simple procedures with excellent production efficiency, reliable output performance, and superior adaptability to the irregular surface of the surroundings where they are applied. Here, recent studies on flexible sensors for sensing humidity and strain/pressure are outlined, emphasizing their sensory materials, working mechanisms, structures, fabrication methods, and particular applications. Furthermore, a conclusion, including future perspectives and a short overview of the market share in this field, is given for further advancing this field of research. Full article
(This article belongs to the Topic Advanced Nanomaterials for Sensing Applications)
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10 pages, 2240 KiB  
Article
Preparation of Salt-Induced Ultra-Stretchable Nanocellulose Composite Hydrogel for Self-Powered Sensors
by Xiaofa Wang, Xincai Li, Baobin Wang, Jiachuan Chen, Lei Zhang, Kai Zhang, Ming He, Yu Xue and Guihua Yang
Nanomaterials 2023, 13(1), 157; https://doi.org/10.3390/nano13010157 - 29 Dec 2022
Cited by 8 | Viewed by 2427
Abstract
Hydrogels have attracted much attraction for promising flexible electronics due to the versatile tunability of the properties. However, there is still a big obstacle to balance between the multi-properties and performance of wearable electronics. Herein, we propose a salt-percolated nanocellulose composite hydrogel which [...] Read more.
Hydrogels have attracted much attraction for promising flexible electronics due to the versatile tunability of the properties. However, there is still a big obstacle to balance between the multi-properties and performance of wearable electronics. Herein, we propose a salt-percolated nanocellulose composite hydrogel which was fabricated via radical polymerization with acrylic acid as polymer networks (NaCl-CNCs-PAA). CNCs were utilized as a reinforcing agent to enhance the mechanical properties of the hydrogel. Moreover, the abundant hydroxyl groups endow the hydrogel with noncovalent interactions, such as hydrogen bonding, and the robustness of the hydrogel was thus improved. NaCl incorporation induced the electrostatic interaction between CNCs and PAA polymer blocks, thus facilitating the improvement of the stretchability of the hydrogel. The as-obtained hydrogel exhibited excellent stretchability, ionic conductivity, mechanical robustness and anti-freezing properties, making it suitable for self-powered sensing applications. A single-mode triboelectric nanogenerator (C-TENG) was fabricated by utilizing the composite hydrogel as electrodes. This C-TENG could effectively convert biomechanical energy to electricity (89.2 V, 1.8 µA, 32.1 nC, and the max power density of 60.8 mW m−2 at 1.5 Hz.) Moreover, the composite hydrogel was applied for strain sensing to detect human motions. The nanocellulose composite hydrogel can achieve the application as a power supply in integrated sensing systems and as a strain sensor for human motion detection. Full article
(This article belongs to the Topic Advanced Nanomaterials for Sensing Applications)
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11 pages, 2302 KiB  
Article
Flexible SbSI/Polyurethane Nanocomposite for Sensing and Energy Harvesting
by Bartłomiej Nowacki, Jakub Jała, Krystian Mistewicz, Roman Przyłucki, Grzegorz Kopeć and Tomasz Stenzel
Sensors 2023, 23(1), 63; https://doi.org/10.3390/s23010063 - 21 Dec 2022
Viewed by 2013
Abstract
The dynamic development of flexible wearable electronics creates new possibilities for the production and use of new types of sensors. Recently, polymer nanocomposites have gained great popularity in the fabrication of sensors. They possess both the mechanical advantages of polymers and the functional [...] Read more.
The dynamic development of flexible wearable electronics creates new possibilities for the production and use of new types of sensors. Recently, polymer nanocomposites have gained great popularity in the fabrication of sensors. They possess both the mechanical advantages of polymers and the functional properties of nanomaterials. The main drawback of such systems is the complexity of their manufacturing. This article presents, for the first time, fabrication of an antimony sulfoiodide (SbSI) and polyurethane (PU) nanocomposite and its application as a piezoelectric nanogenerator for strain detection. The SbSI/PU nanocomposite was prepared using simple, fast, and efficient technology. It allowed the obtainment of a high amount of material without the need to apply complex chemical methods or material processing. The SbSI/PU nanocomposite exhibited high flexibility and durability. The microstructure and chemical composition of the prepared material were investigated using scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDS), respectively. These studies revealed a lack of defects in the material structure and relatively low agglomeration of nanowires. The piezoelectric response of SbSI/PU nanocomposite was measured by pressing the sample with a pneumatic actuator at different excitation frequencies. It is proposed that the developed nanocomposite can be introduced into the shoe sole in order to harvest energy from human body movement. Full article
(This article belongs to the Topic Advanced Nanomaterials for Sensing Applications)
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36 pages, 6115 KiB  
Review
Nanomaterials-Based Ion-Imprinted Electrochemical Sensors for Heavy Metal Ions Detection: A Review
by Liangyun Yu, Liangju Sun, Qi Zhang, Yawen Zhou, Jingjing Zhang, Bairen Yang, Baocai Xu and Qin Xu
Biosensors 2022, 12(12), 1096; https://doi.org/10.3390/bios12121096 - 30 Nov 2022
Cited by 23 | Viewed by 4007
Abstract
Heavy metal ions (HMIs) pose a serious threat to the environment and human body because they are toxic and non-biodegradable and widely exist in environmental ecosystems. It is necessary to develop a rapid, sensitive and convenient method for HMIs detection to provide a [...] Read more.
Heavy metal ions (HMIs) pose a serious threat to the environment and human body because they are toxic and non-biodegradable and widely exist in environmental ecosystems. It is necessary to develop a rapid, sensitive and convenient method for HMIs detection to provide a strong guarantee for ecology and human health. Ion-imprinted electrochemical sensors (IIECSs) based on nanomaterials have been regarded as an excellent technology because of the good selectivity, the advantages of fast detection speed, low cost, and portability. Electrode surfaces modified with nanomaterials can obtain excellent nano-effects, such as size effect, macroscopic quantum tunneling effect and surface effect, which greatly improve its surface area and conductivity, so as to improve the detection sensitivity and reduce the detection limit of the sensor. Hence, the present review focused on the fundamentals and the synthetic strategies of ion-imprinted polymers (IIPs) and IIECSs for HMIs detection, as well as the applications of various nanomaterials as modifiers and sensitizers in the construction of HMIIECSs and the influence on the sensing performance of the fabricated sensors. Finally, the potential challenges and outlook on the future development of the HMIIECSs technology were also highlighted. By means of the points presented in this review, we hope to provide some help in further developing the preparation methods of high-performance HMIIECSs and expanding their potential applications. Full article
(This article belongs to the Topic Advanced Nanomaterials for Sensing Applications)
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11 pages, 2458 KiB  
Article
All-Optical Nanosensor for Displacement Detection in Mechanical Applications
by Lorena Escandell, Carlos Álvarez-Rodríguez, Ángela Barreda, Ramón Zaera and Braulio García-Cámara
Nanomaterials 2022, 12(22), 4107; https://doi.org/10.3390/nano12224107 - 21 Nov 2022
Viewed by 2027
Abstract
In this paper, we propose the design of an optical system based on two parallel suspended silicon nanowires that support a range of optical resonances that efficiently confine and scatter light in the infrared range as the base of an all-optical displacement sensor. [...] Read more.
In this paper, we propose the design of an optical system based on two parallel suspended silicon nanowires that support a range of optical resonances that efficiently confine and scatter light in the infrared range as the base of an all-optical displacement sensor. The effects of the variation of the distance between the nanowires are analyzed. The simulation models are designed by COMSOL Multiphysics software, which is based on the finite element method. The diameter of the nanocylinders (d = 140 nm) was previously optimized to achieve resonances at the operating wavelengths (λ = 1064 nm and 1310 nm). The results pointed out that a detectable change in their resonant behavior and optical interaction was achieved. The proposed design aims to use a simple light source using a commercial diode laser and simplify the readout systems with a high sensitivity of 1.1 × 106 V/m2 and 1.14 × 106 V/m2 at 1064 nm and 1310 nm, respectively. The results may provide an opportunity to investigate alternative designs of displacement sensors from an all-optical approach and explore their potential use. Full article
(This article belongs to the Topic Advanced Nanomaterials for Sensing Applications)
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20 pages, 5067 KiB  
Article
High-Performance Room-Temperature NO2 Gas Sensor Based on Au-Loaded SnO2 Nanowires under UV Light Activation
by Bo Zhang, Shuai Zhang, Yi Xia, Pingping Yu, Yin Xu, Yue Dong, Qufu Wei and Jing Wang
Nanomaterials 2022, 12(22), 4062; https://doi.org/10.3390/nano12224062 - 18 Nov 2022
Cited by 13 | Viewed by 2669
Abstract
Optical excitation is widely acknowledged as one of the most effective means of balancing sensor responses and response/recovery properties at room temperature (RT, 25 °C). Moreover, noble metals have been proven to be suitable as photosensitizers for optical excitation. Localized surface plasmon resonance [...] Read more.
Optical excitation is widely acknowledged as one of the most effective means of balancing sensor responses and response/recovery properties at room temperature (RT, 25 °C). Moreover, noble metals have been proven to be suitable as photosensitizers for optical excitation. Localized surface plasmon resonance (LSPR) determines the liberalization of quasi-free electrons in noble metals under light irradiation, and numerous injected electrons in semiconductors will greatly promote the generation of chemisorbed oxygen, thus elevating the sensor response. In this study, pure SnO2 and Au/SnO2 nanowires (NWs) were successfully synthesized through the electrospinning method and validated using XRD, EDS, HRTEM, and XPS. Although a Schottky barrier led to a much higher initial resistance of the Au/SnO2 composite compared with pure SnO2 at RT in the dark, the photoinduced resistance of the Au/SnO2 composite became lower than that of pure SnO2 under UV irradiation with the same intensity, which confirmed the effect of LSPR. Furthermore, when used as sensing materials, a detailed comparison between the sensing properties of pure SnO2 and Au/SnO2 composite toward NO2 in the dark and under UV irradiation highlighted the crucial role of the LSPR effects. In particular, the response of Au/SnO2 NWs toward 5 ppm NO2 could reach 65 at RT under UV irradiation, and the response/recovery time was only 82/42 s, which far exceeded those under Au modification-only or optical excitation-only. Finally, the gas-sensing mechanism corresponding to the change in sensor performance in each case was systematically proposed. Full article
(This article belongs to the Topic Advanced Nanomaterials for Sensing Applications)
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13 pages, 4486 KiB  
Article
WS2 Nanorod as a Remarkable Acetone Sensor for Monitoring Work/Public Places
by Rajneesh Kumar Mishra, Vipin Kumar, Le Gia Trung, Gyu Jin Choi, Jeong Won Ryu, Sagar M. Mane, Jae Cheol Shin, Pushpendra Kumar, Seung Hee Lee and Jin Seog Gwag
Sensors 2022, 22(22), 8609; https://doi.org/10.3390/s22228609 - 8 Nov 2022
Cited by 5 | Viewed by 2261
Abstract
Here, we report the synthesis of the WS2 nanorods (NRs) using an eco-friendly and facile hydrothermal method for an acetone-sensing application. This study explores the acetone gas-sensing characteristics of the WS2 nanorod sensor for 5, 10, and 15 ppm concentrations at [...] Read more.
Here, we report the synthesis of the WS2 nanorods (NRs) using an eco-friendly and facile hydrothermal method for an acetone-sensing application. This study explores the acetone gas-sensing characteristics of the WS2 nanorod sensor for 5, 10, and 15 ppm concentrations at 25 °C, 50 °C, 75 °C, and 100 °C. The WS2 nanorod sensor shows the highest sensitivity of 94.5% at 100 °C for the 15 ppm acetone concentration. The WS2 nanorod sensor also reveals the outstanding selectivity of acetone compared to other gases, such as ammonia, ethanol, acetaldehyde, methanol, and xylene at 100 °C with a 15 ppm concentration. The estimated selectivity coefficient indicates that the selectivity of the WS2 nanorod acetone sensor is 7.1, 4.5, 3.7, 2.9, and 2.0 times higher than xylene, acetaldehyde, ammonia, methanol, and ethanol, respectively. In addition, the WS2 nanorod sensor also divulges remarkable stability of 98.5% during the 20 days of study. Therefore, it is concluded that the WS2 nanorod can be an excellent nanomaterial for developing acetone sensors for monitoring work/public places. Full article
(This article belongs to the Topic Advanced Nanomaterials for Sensing Applications)
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12 pages, 10194 KiB  
Article
Does Size Matter? The Case of Piezoresistive Properties of Carbon Nanotubes/Elastomer Nanocomposite Synthesized through Mechanochemistry
by Antonio Turco, Anna Grazia Monteduro, Francesco Montagna, Elisabetta Primiceri, Mariaenrica Frigione and Giuseppe Maruccio
Nanomaterials 2022, 12(21), 3741; https://doi.org/10.3390/nano12213741 - 25 Oct 2022
Cited by 4 | Viewed by 1765
Abstract
The growing interest in piezoresistive sensors has favored the development of numerous approaches and materials for their fabrication. Within this framework, carbon nanotubes (CNTs) are often employed. However, CNTs are a heterogeneous material with different morphological characteristics in terms of length and diameter, [...] Read more.
The growing interest in piezoresistive sensors has favored the development of numerous approaches and materials for their fabrication. Within this framework, carbon nanotubes (CNTs) are often employed. However, CNTs are a heterogeneous material with different morphological characteristics in terms of length and diameter, and, so far, experimental studies have not usually considered the effect of these parameters on the final sensor performances. Here, we observe how, by simply changing the CNTs length in a solvent-free mechanochemistry fabrication method, different porous 3D elastomeric nanocomposites with different electrical and mechanical properties can be obtained. In particular, the use of longer carbon nanotubes allows the synthesis of porous nanocomposites with better mechanical stability and conductivity, and with a nine-times-lower limit of detection (namely 0.2 Pa) when used as a piezoresistive sensor. Moreover, the material prepared with longer carbon nanotubes evidenced a faster recovery of its shape and electrical properties during press/release cycles, thus allowing faster response at different pressures. These results provide evidence as to how CNTs length can be a key aspect in obtaining piezoresistive sensors with better properties. Full article
(This article belongs to the Topic Advanced Nanomaterials for Sensing Applications)
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11 pages, 2911 KiB  
Article
Effects of Boric Acid and Storage Temperature on the Analysis of Microalbumin Using Aptasensor-Based Fluorescent Detection
by Chalermwoot Sompark, Wireeya Chawjiraphan, Manatsaphon Sukmak, Ubon Cha’on, Sirirat Anutrakulchai, Prapasiri Pongprayoon, Thitirat Putnin, Dechnarong Pimalai, Visarute Pinrod and Deanpen Japrung
Biosensors 2022, 12(11), 915; https://doi.org/10.3390/bios12110915 - 24 Oct 2022
Cited by 3 | Viewed by 2593
Abstract
The instability of human serum albumin (HSA) in urine samples makes fresh urine a requirement for microalbumin analyses using immunoturbidimetry. Here, we determined the ability of an aptasensor-based fluorescent platform to detect microalbumin in old, boric acid-preserved urine samples. Our results show that [...] Read more.
The instability of human serum albumin (HSA) in urine samples makes fresh urine a requirement for microalbumin analyses using immunoturbidimetry. Here, we determined the ability of an aptasensor-based fluorescent platform to detect microalbumin in old, boric acid-preserved urine samples. Our results show that the cleavage site of protease enzymes on urine albumin protein differed from the binding position of the aptamer on HSA protein, suggesting the aptasensor may be effective for albumin detection in non-fresh urine. Furthermore, the addition of boric acid in urine samples over a short term (at ambient temperature (Ta) and 4 °C), long term (−20 and −80 °C), and following freeze–thawing (1–3 cycles) did not significantly affect albumin stability, as analyzed using the aptasensor. Therefore, boric acid stabilized has in urine stored over a short- and long-term. Thus, the aptasensor developed by us is applicable for HSA detection in boric acid-preserved urine that has been stored for 7-d at Ta and 4 °C, and in the long-term at −80 °C. Full article
(This article belongs to the Topic Advanced Nanomaterials for Sensing Applications)
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10 pages, 6618 KiB  
Article
Highly Sensitive Acetone Gas Sensors Based on Erbium-Doped Bismuth Ferrite Nanoparticles
by Xiaolian Liu, Jing Li, Lanlan Guo and Guodong Wang
Nanomaterials 2022, 12(20), 3679; https://doi.org/10.3390/nano12203679 - 20 Oct 2022
Cited by 6 | Viewed by 1887
Abstract
The acetone-sensing performance of BiFeO3 is related to structural phase transformation, morphology and band gap energy which can be modulated by rare-earth ions doping. In this work, Bi1−xErxFeO3 nanoparticles with different amounts of Er doping were synthesized [...] Read more.
The acetone-sensing performance of BiFeO3 is related to structural phase transformation, morphology and band gap energy which can be modulated by rare-earth ions doping. In this work, Bi1−xErxFeO3 nanoparticles with different amounts of Er doping were synthesized via the sol-gel method. The mechanism of Er doping on acetone-sensing performance of Bi1−xErxFeO3 (x = 0, 0.05, 0.1 and 0.2) sensors was the focus of the research. The optimal working temperature of Bi0.9Er0.1FeO3 (300 °C) was decreased by 60 °C compared to BiFeO3 (360 °C). The Bi0.9Er0.1FeO3 sample demonstrated the optimal response to 100 ppm acetone (43.2), which was 4.8 times that of pure BFO at 300 °C. The primary reason, which enhances the acetone-sensing performance, could be the phase transformation induced by Er doping. The lattice distortions induced by phase transformation are favorable to increasing the carrier concentration and mobility, which will bring more changes to the hole-accumulation layer. Thus, the acetone-sensing performance of Bi0.9Er0.1FeO3 was improved. Full article
(This article belongs to the Topic Advanced Nanomaterials for Sensing Applications)
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13 pages, 5655 KiB  
Article
Temperature Dependence of Electrical Resistance in Carbon Nanotube Composite Film during Curing Process
by Fei Xing, Min Li, Shaokai Wang, Yizhuo Gu, Wei Zhang and Yanjie Wang
Nanomaterials 2022, 12(20), 3552; https://doi.org/10.3390/nano12203552 - 11 Oct 2022
Cited by 4 | Viewed by 2085
Abstract
Carbon nanotube (CNT) film possesses excellent mechanical and piezoresistivity, which may act as a sensor for process monitoring and reinforcement of the final composite. This paper prepared CNT/epoxy composite film via the solution dipping method and investigated the electrical resistance variation (ΔR/R [...] Read more.
Carbon nanotube (CNT) film possesses excellent mechanical and piezoresistivity, which may act as a sensor for process monitoring and reinforcement of the final composite. This paper prepared CNT/epoxy composite film via the solution dipping method and investigated the electrical resistance variation (ΔR/R0) of CNT/epoxy composite film during the curing process. The temperature dependence of electrical resistance was found to be closely related to resin rheological properties, thermal expansion, and curing shrinkage. The results show that two opposing effects on electrical resistivity occur at the initial heating stage, including thermal expansion and condensation caused by the wetting tension of the liquid resin. The lower resin content causes more apparent secondary impregnation and electrical resistivity change. When the resin viscosity remains steady during the heating stage, the electrical resistance increases with an increase in temperature due to thermal expansion. Approaching gel time, the electrical resistance drops due to the crosslink shrinkage of epoxy resin. The internal stress caused by curing shrinkage at the high-temperature platform results in an increase in electrical resistance. The temperature coefficient of resistance becomes larger with an increase in resin content. At the isothermal stage, an increase in ΔR/R0 value becomes less obvious with a decrease in resin content, and ΔR/R0 even shows a decreasing tendency. Full article
(This article belongs to the Topic Advanced Nanomaterials for Sensing Applications)
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14 pages, 4288 KiB  
Article
Hybrid Carbon Nanotubes/Gold Nanoparticles Composites for Trace Nitric Oxide Detection over a Wide Range of Humidity
by Ami Hannon, Wayne Seames and Jing Li
Sensors 2022, 22(19), 7581; https://doi.org/10.3390/s22197581 - 6 Oct 2022
Cited by 2 | Viewed by 2771
Abstract
Composites of functionalized single walled carbon nanotubes (SWCNTs) and gold nanoparticles (Au NPs) of ≈15 nm diameter were drop-cast on a printed circuit board (PCB) substrate equipped with interdigitated electrodes to make a hybrid thin film. Addition of Au NPs decorated the surface [...] Read more.
Composites of functionalized single walled carbon nanotubes (SWCNTs) and gold nanoparticles (Au NPs) of ≈15 nm diameter were drop-cast on a printed circuit board (PCB) substrate equipped with interdigitated electrodes to make a hybrid thin film. Addition of Au NPs decorated the surface of SWCNTs networked films and acted as catalysts which resulted into an enhanced sensitivity and low ppb concentration detection limit. The compositions of the film were characterized by scanning electron microscope (SEM). SWCNTs clusters were loaded with various amount of Au NPs ranging from 1–10% (by weight) and their effect on Nitric oxide (NO) sensitivity was studied and optimized. Further, the optimized composite films were tested in both air and nitrogen environments and as well as over a wide relative humidity range (0–97%). Sensors were also tested for the selectivity by exposing to various gases such as nitrous oxide, ammonia, carbon monoxide, sulfur dioxide and acetone. Sensitivity to NO was found much higher than the other tested gases. The advantage of this sensor is that it is sensitive to NO at low ppb level (10 ppb) with estimated response time within 10 s and recovery time around 1 min, and has excellent reproducibility from sensor to sensor and works within the wide range of relative humidity (0–97%). Full article
(This article belongs to the Topic Advanced Nanomaterials for Sensing Applications)
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8 pages, 2676 KiB  
Communication
Cr-MOF-Based Electrochemical Sensor for the Detection of P-Nitrophenol
by Chao Hu, Ping Pan, Haiping Huang and Hongtao Liu
Biosensors 2022, 12(10), 813; https://doi.org/10.3390/bios12100813 - 1 Oct 2022
Cited by 18 | Viewed by 3109
Abstract
Cr-MOF nanoparticles were synthesized by a simple hydrothermal method, and their morphology and structure were characterized by SEM, TEM, and XRD techniques. The Cr-MOF modified glassy carbon electrode (Cr-MOF/GCE) was well constructed and served as an efficient electrochemical sensor for the detection of [...] Read more.
Cr-MOF nanoparticles were synthesized by a simple hydrothermal method, and their morphology and structure were characterized by SEM, TEM, and XRD techniques. The Cr-MOF modified glassy carbon electrode (Cr-MOF/GCE) was well constructed and served as an efficient electrochemical sensor for the detection of p-nitrophenol (p-NP). It was found that the Cr-MOF nanoparticles had significant electrocatalytic activity toward the reduction of p-NP. The Cr-MOF-based electrochemical sensor exhibited a low detection limit of 0.7 μM for p-NP in a wide range of 2~500 μM and could maintain excellent detection stability in a series of interfering media. The electrochemical sensor was also practically applied to detect p-NP in a local river and confirmed its validity, showing potential application prospects. Full article
(This article belongs to the Topic Advanced Nanomaterials for Sensing Applications)
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17 pages, 3122 KiB  
Review
Electrochemical Microneedles: Innovative Instruments in Health Care
by Zhijun Liao, Qian Zhou and Bingbing Gao
Biosensors 2022, 12(10), 801; https://doi.org/10.3390/bios12100801 - 28 Sep 2022
Cited by 7 | Viewed by 3674
Abstract
As a significant part of drug therapy, the mode of drug transport has attracted worldwide attention. Efficient drug delivery methods not only markedly improve the drug absorption rate, but also reduce the risk of infection. Recently, microneedles have combined the advantages of subcutaneous [...] Read more.
As a significant part of drug therapy, the mode of drug transport has attracted worldwide attention. Efficient drug delivery methods not only markedly improve the drug absorption rate, but also reduce the risk of infection. Recently, microneedles have combined the advantages of subcutaneous injection administration and transdermal patch administration, which is not only painless, but also has high drug absorption efficiency. In addition, microneedle-based electrochemical sensors have unique capabilities for continuous health state monitoring, playing a crucial role in the real-time monitoring of various patient physiological indicators. Therefore, they are commonly applied in both laboratories and hospitals. There are a variety of reports regarding electrochemical microneedles; however, the comprehensive introduction of new electrochemical microneedles is still rare. Herein, significant work on electrochemical microneedles over the past two years is summarized, and the main challenges faced by electrochemical microneedles and future development directions are proposed. Full article
(This article belongs to the Topic Advanced Nanomaterials for Sensing Applications)
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23 pages, 20533 KiB  
Article
UV-Cured Green Polymers for Biosensorics: Correlation of Operational Parameters of Highly Sensitive Biosensors with Nano-Volumes and Adsorption Properties
by Magdalena Goździuk, Taras Kavetskyy, Daniel Massana Roquero, Oleh Smutok, Mykhailo Gonchar, David P. Královič, Helena Švajdlenková, Ondrej Šauša, Pavol Kalinay, Hamed Nosrati, Migle Lebedevaite, Sigita Grauzeliene, Jolita Ostrauskaite, Arnold Kiv and Bożena Zgardzińska
Materials 2022, 15(19), 6607; https://doi.org/10.3390/ma15196607 - 23 Sep 2022
Cited by 5 | Viewed by 2134
Abstract
The investigated polymeric matrixes consisted of epoxidized linseed oil (ELO), acrylated epoxidized soybean oil (AESO), trimethylolpropane triglycidyl ether (RD1), vanillin dimethacrylate (VDM), triarylsulfonium hexafluorophosphate salts (PI), and 2,2-dimethoxy-2-phenylacetophenone (DMPA). Linseed oil-based (ELO/PI, ELO/10RD1/PI) and soybean oil-based (AESO/VDM, AESO/VDM/DMPA) polymers were obtained by cationic [...] Read more.
The investigated polymeric matrixes consisted of epoxidized linseed oil (ELO), acrylated epoxidized soybean oil (AESO), trimethylolpropane triglycidyl ether (RD1), vanillin dimethacrylate (VDM), triarylsulfonium hexafluorophosphate salts (PI), and 2,2-dimethoxy-2-phenylacetophenone (DMPA). Linseed oil-based (ELO/PI, ELO/10RD1/PI) and soybean oil-based (AESO/VDM, AESO/VDM/DMPA) polymers were obtained by cationic and radical photopolymerization reactions, respectively. In order to improve the cross-linking density of the resulting polymers, 10 mol.% of RD1 was used as a reactive diluent in the cationic photopolymerization of ELO. In parallel, VDM was used as a plasticizer in AESO radical photopolymerization reactions. Positron annihilation lifetime spectroscopy (PALS) was used to characterize vegetable oil-based UV-cured polymers regarding their structural stability in a wide range of temperatures (120–320 K) and humidity. The polymers were used as laccase immobilization matrixes for the construction of amperometric biosensors. A direct dependence of the main operational parameters of the biosensors and microscopical characteristics of polymer matrixes (mostly on the size of free volumes and water content) was established. The biosensors are intended for the detection of trace water pollution with xenobiotics, carcinogenic substances with a very negative impact on human health. These findings will allow better predictions for novel polymers as immobilization matrixes for biosensing or biotechnology applications. Full article
(This article belongs to the Topic Advanced Nanomaterials for Sensing Applications)
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16 pages, 5247 KiB  
Article
High-Efficiency Utilization of Waste Tobacco Stems to Synthesize Novel Biomass-Based Carbon Dots for Precise Detection of Tetracycline Antibiotic Residues
by Hui Yang, Yunlong Wei, Xiufang Yan, Chao Nie, Zhenchun Sun, Likai Hao and Xiankun Su
Nanomaterials 2022, 12(18), 3241; https://doi.org/10.3390/nano12183241 - 18 Sep 2022
Cited by 7 | Viewed by 2467
Abstract
Recycling waste biomass into valuable products (e.g., nanomaterials) is of considerable theoretical and practical significance to achieve future sustainable development. Here, we propose a one-pot hydrothermal synthesis route to convert waste tobacco stems into biomass-based N, S-codoped carbon dots (C−dots) with the assistance [...] Read more.
Recycling waste biomass into valuable products (e.g., nanomaterials) is of considerable theoretical and practical significance to achieve future sustainable development. Here, we propose a one-pot hydrothermal synthesis route to convert waste tobacco stems into biomass-based N, S-codoped carbon dots (C−dots) with the assistance of carbon black. Unlike most of the previously reported luminescent C−dots, these biomass-based C−dots showed a satisfactory stability, as well as an excitation-independent fluorescence emission at ~520 nm. Furthermore, they demonstrated a pH-dependent fluorescence emission ability, offering a scaffold to design pH-responsive assays. Moreover, these as-synthesized biomass-based C−dots exhibited a fluorescence response ability toward tetracycline antibiotics (TCs, e.g., TC, CTC, and OTC) through the inner filter effect (IFE), thereby allowing for the establishment a smart analytical platform to sensitively and selectively monitor residual TCs in real environmental water samples. In this study, we explored the conversion of waste tobacco stems into sustainable biomass-based C−dots to develop simple, efficient, label-free, reliable, low-cost, and eco-friendly analytical platforms for environmental pollution traceability analysis, which might provide a novel insight to resolve the ecological and environmental issues derived from waste tobacco stems. Full article
(This article belongs to the Topic Advanced Nanomaterials for Sensing Applications)
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16 pages, 7473 KiB  
Article
Using Femtosecond Laser Pulses to Explore the Nonlinear Optical Properties of Au NP Colloids That Were Synthesized by Laser Ablation
by Mohamed Ashour, Hameed G. Faris, Hanan Ahmed, Samar Mamdouh, Kavintheran Thambiratnam and Tarek Mohamed
Nanomaterials 2022, 12(17), 2980; https://doi.org/10.3390/nano12172980 - 28 Aug 2022
Cited by 10 | Viewed by 2449
Abstract
In this study, we experimentally investigated the nonlinear optical properties of Au nanoparticles (Au NPs) that were prepared in pure distilled water using the laser ablation method. The Au NPs were prepared using a nanosecond Nd:YAG laser with an ablation time of 5 [...] Read more.
In this study, we experimentally investigated the nonlinear optical properties of Au nanoparticles (Au NPs) that were prepared in pure distilled water using the laser ablation method. The Au NPs were prepared using a nanosecond Nd:YAG laser with an ablation time of 5 or 10 min at a constant laser energy of 100 mJ. The structure and the linear optical properties of the Au NPs were investigated using a transmission electron microscope (TEM) and UV-visible spectrophotometer analysis, respectively. The TEM measurements showed that the average size of the Au NPs varied from 20.3 to 14.1 nm, depending on the laser ablation time. The z-scan technique was used to investigate the nonlinear refractive index (n2) and nonlinear absorption coefficient (γ) of the Au NPs, which were irradiated at different excitation wavelengths that ranged from 740 to 820 nm and at different average powers that ranged from 0.8 to 1.6 W. The Au NP samples exhibited a reverse saturable absorption (RSA) behavior that increased when the excitation wavelength and/or incident laser power increased. In addition, the Au NPs acted as a self-defocusing material whenever the excitation wavelength or incident power were modified. Full article
(This article belongs to the Topic Advanced Nanomaterials for Sensing Applications)
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23 pages, 5306 KiB  
Article
Nano-Sheet-like Morphology of Nitrogen-Doped Graphene-Oxide-Grafted Manganese Oxide and Polypyrrole Composite for Chemical Warfare Agent Simulant Detection
by Sanjeeb Lama, Bong-Gyu Bae, Sivalingam Ramesh, Young-Jun Lee, Namjin Kim and Joo-Hyung Kim
Nanomaterials 2022, 12(17), 2965; https://doi.org/10.3390/nano12172965 - 27 Aug 2022
Cited by 8 | Viewed by 2464
Abstract
Chemical warfare agents (CWAs) have inflicted monumental damage to human lives from World War I to modern warfare in the form of armed conflict, terrorist attacks, and civil wars. Is it possible to detect the CWAs early and prevent the loss of human [...] Read more.
Chemical warfare agents (CWAs) have inflicted monumental damage to human lives from World War I to modern warfare in the form of armed conflict, terrorist attacks, and civil wars. Is it possible to detect the CWAs early and prevent the loss of human lives? To answer this research question, we synthesized hybrid composite materials to sense CWAs using hydrothermal and thermal reduction processes. The synthesized hybrid composite materials were evaluated with quartz crystal microbalance (QCM) and surface acoustic wave (SAW) sensors as detectors. The main findings from this study are: (1) For a low dimethyl methyl phosphonate (DMMP) concentration of 25 ppm, manganese dioxide nitrogen-doped graphene oxide (NGO@MnO2) and NGO@MnO2/Polypyrrole (PPy) showed the sensitivities of 7 and 51 Hz for the QCM sensor and 146 and 98 Hz for the SAW sensor. (2) NGO@MnO2 and NGO@MnO2/PPy showed sensitivities of more than 50-fold in the QCM sensor and 100-fold in the SAW sensor between DMMP and potential interferences. (3) NGO@MnO2 and NGO@MnO2/PPy showed coefficients of determination (R2) of 0.992 and 0.975 for the QCM sensor and 0.979 and 0.989 for the SAW sensor. (4) NGO@MnO2 and NGO@MnO2/PPy showed repeatability of 7.00 ± 0.55 and 47.29 ± 2.69 Hz in the QCM sensor and 656.37 ± 73.96 and 665.83 ± 77.50 Hz in the SAW sensor. Based on these unique findings, we propose NGO@MnO2 and NGO@MnO2/PPy as potential candidate materials that could be used to detect CWAs. Full article
(This article belongs to the Topic Advanced Nanomaterials for Sensing Applications)
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10 pages, 5567 KiB  
Communication
Piezoresistance Characterization of Silicon Nanowires in Uniaxial and Isostatic Pressure Variation
by Elham Fakhri, Rodica Plugaru, Muhammad Taha Sultan, Thorsteinn Hanning Kristinsson, Hákon Örn Árnason, Neculai Plugaru, Andrei Manolescu, Snorri Ingvarsson and Halldor Gudfinnur Svavarsson
Sensors 2022, 22(17), 6340; https://doi.org/10.3390/s22176340 - 23 Aug 2022
Cited by 6 | Viewed by 2253
Abstract
Silicon nanowires (SiNWs) are known to exhibit a large piezoresistance (PZR) effect, making them suitable for various sensing applications. Here, we report the results of a PZR investigation on randomly distributed and interconnected vertical silicon nanowire arrays as a pressure sensor. The samples [...] Read more.
Silicon nanowires (SiNWs) are known to exhibit a large piezoresistance (PZR) effect, making them suitable for various sensing applications. Here, we report the results of a PZR investigation on randomly distributed and interconnected vertical silicon nanowire arrays as a pressure sensor. The samples were produced from p-type (100) Si wafers using a silver catalyzed top-down etching process. The piezoresistance response of these SiNW arrays was analyzed by measuring their I-V characteristics under applied uniaxial as well as isostatic pressure. The interconnected SiNWs exhibit increased mechanical stability in comparison with separated or periodic nanowires. The repeatability of the fabrication process and statistical distribution of measurements were also tested on several samples from different batches. A sensing resolution down to roughly 1m pressure was observed with uniaxial force application, and more than two orders of magnitude resistance variation were determined for isostatic pressure below atmospheric pressure. Full article
(This article belongs to the Topic Advanced Nanomaterials for Sensing Applications)
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15 pages, 3861 KiB  
Article
A Visible-Light-Active CuS/MoS2/Bi2WO6 Aptamer Sensitively Detects the Non-Steroidal Anti-Inflammatory Drug Diclofenac
by Yun He, Hongjie Gao and Jiankang Liu
Nanomaterials 2022, 12(16), 2834; https://doi.org/10.3390/nano12162834 - 18 Aug 2022
Cited by 4 | Viewed by 2600
Abstract
Diclofenac is a non-steroidal, anti-inflammatory drug and is clinically used for the treatment of osteoarthritis, non-articular rheumatism, etc. This research aimed to demonstrate the creation of an upgraded photoelectrochemical (PEC) aptamer sensor for detecting diclofenac (DCF) with high sensitivity. In this work, photoactive [...] Read more.
Diclofenac is a non-steroidal, anti-inflammatory drug and is clinically used for the treatment of osteoarthritis, non-articular rheumatism, etc. This research aimed to demonstrate the creation of an upgraded photoelectrochemical (PEC) aptamer sensor for detecting diclofenac (DCF) with high sensitivity. In this work, photoactive materials and bio-identification components served as visible-light-active CuS/MoS2/Bi2WO6 heterostructures and aptamers, respectively. CuS and MoS2/Bi2WO6 were combined to improve photocurrent responsiveness, which helped the structure of PEC aptasensors. Additionally, the one-pot synthesis of CuS/MoS2/Bi2WO6 was ecologically beneficial. With these optimizations, the photocurrent response of aptamer/CS/CuS/MoS2/Bi2WO6 exhibited linearity between 0.1 and 500 nM DCF. The detection limit was 0.03 nM (S/N = 3). These results suggest that the PEC sensing technique might produce an ultra-sensitive sensor with high selectivity and stability for DCF detection. Full article
(This article belongs to the Topic Advanced Nanomaterials for Sensing Applications)
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17 pages, 9898 KiB  
Review
Chemical Sensor Nanotechnology in Pharmaceutical Drug Research
by Lebogang Thobakgale, Saturnin Ombinda-Lemboumba and Patience Mthunzi-Kufa
Nanomaterials 2022, 12(15), 2688; https://doi.org/10.3390/nano12152688 - 5 Aug 2022
Cited by 7 | Viewed by 3347
Abstract
The increase in demand for pharmaceutical treatments due to pandemic-related illnesses has created a need for improved quality control in drug manufacturing. Understanding the physical, biological, and chemical properties of APIs is an important area of health-related research. As such, research into enhanced [...] Read more.
The increase in demand for pharmaceutical treatments due to pandemic-related illnesses has created a need for improved quality control in drug manufacturing. Understanding the physical, biological, and chemical properties of APIs is an important area of health-related research. As such, research into enhanced chemical sensing and analysis of pharmaceutical ingredients (APIs) for drug development, delivery and monitoring has become immensely popular in the nanotechnology space. Nanomaterial-based chemical sensors have been used to detect and analyze APIs related to the treatment of various illnesses pre and post administration. Furthermore, electrical and optical techniques are often coupled with nano-chemical sensors to produce data for various applications which relate to the efficiencies of the APIs. In this review, we focus on the latest nanotechnology applied to probing the chemical and biochemical properties of pharmaceutical drugs, placing specific interest on several types of nanomaterial-based chemical sensors, their characteristics, detection methods, and applications. This study offers insight into the progress in drug development and monitoring research for designing improved quality control methods for pharmaceutical and health-related research. Full article
(This article belongs to the Topic Advanced Nanomaterials for Sensing Applications)
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17 pages, 2632 KiB  
Perspective
Paper-Based Molecular-Imprinting Technology and Its Application
by Shufang Xu, Zhigang Xu and Zhimin Liu
Biosensors 2022, 12(8), 595; https://doi.org/10.3390/bios12080595 - 3 Aug 2022
Cited by 20 | Viewed by 3801
Abstract
Paper-based analytical devices (PADs) are highly effective tools due to their low cost, portability, low reagent accumulation, and ease of use. Molecularly imprinted polymers (MIP) are also extensively used as biomimetic receptors and specific adsorption materials for capturing target analytes in various complex [...] Read more.
Paper-based analytical devices (PADs) are highly effective tools due to their low cost, portability, low reagent accumulation, and ease of use. Molecularly imprinted polymers (MIP) are also extensively used as biomimetic receptors and specific adsorption materials for capturing target analytes in various complex matrices due to their excellent recognition ability and structural stability. The integration of MIP and PADs (MIP-PADs) realizes the rapid, convenient, and low-cost application of molecular-imprinting analysis technology. This review introduces the characteristics of MIP-PAD technology and discusses its application in the fields of on-site environmental analysis, food-safety monitoring, point-of-care detection, biomarker detection, and exposure assessment. The problems and future development of MIP-PAD technology in practical application are also prospected. Full article
(This article belongs to the Topic Advanced Nanomaterials for Sensing Applications)
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9 pages, 1978 KiB  
Article
An LSPR Sensor Integrated with VCSEL and Microfluidic Chip
by Fang Cao, Xupeng Zhao, Xiaoqing Lv, Liangchen Hu, Wenhui Jiang, Feng Yang, Li Chi, Pengying Chang, Chen Xu and Yiyang Xie
Nanomaterials 2022, 12(15), 2607; https://doi.org/10.3390/nano12152607 - 29 Jul 2022
Cited by 3 | Viewed by 2308
Abstract
The work introduces a localized surface plasmon resonance (LSPR) sensor chip integrated with vertical-cavity surface-emitting lasers (VCSELs). Using VCSEL as the light source, the hexagonal gold nanoparticle array was integrated with anodic aluminum oxide (AAO) as the mask on the light-emitting end face. [...] Read more.
The work introduces a localized surface plasmon resonance (LSPR) sensor chip integrated with vertical-cavity surface-emitting lasers (VCSELs). Using VCSEL as the light source, the hexagonal gold nanoparticle array was integrated with anodic aluminum oxide (AAO) as the mask on the light-emitting end face. The sensitivity sensing test of the refractive index solution was realized, combined with microfluidic technology. At the same time, the finite-difference time- domain (FDTD) algorithm was applied to model and simulate the gold nanostructures. The experimental results showed that the output power of the sensor was related to the refractive index of the sucrose solution. The maximum sensitivity of the sensor was 1.65 × 106 nW/RIU, which gives it great application potential in the field of biomolecular detection. Full article
(This article belongs to the Topic Advanced Nanomaterials for Sensing Applications)
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12 pages, 2435 KiB  
Article
Insight into a Fenton-like Reaction Using Nanodiamond Based Relaxometry
by Sandeep Kumar Padamati, Thea Annie Vedelaar, Felipe Perona Martínez, Anggrek Citra Nusantara and Romana Schirhagl
Nanomaterials 2022, 12(14), 2422; https://doi.org/10.3390/nano12142422 - 15 Jul 2022
Cited by 6 | Viewed by 2433
Abstract
Copper has several biological functions, but also some toxicity, as it can act as a catalyst for oxidative damage to tissues. This is especially relevant in the presence of H2O2, a by-product of oxygen metabolism. In this study, the [...] Read more.
Copper has several biological functions, but also some toxicity, as it can act as a catalyst for oxidative damage to tissues. This is especially relevant in the presence of H2O2, a by-product of oxygen metabolism. In this study, the reactions of copper with H2O2 have been investigated with spectroscopic techniques. These results were complemented by a new quantum sensing technique (relaxometry), which allows nanoscale magnetic resonance measurements at room temperature, and at nanomolar concentrations. For this purpose, we used fluorescent nanodiamonds (FNDs) containing ensembles of specific defects called nitrogen-vacancy (NV) centers. More specifically, we performed so-called T1 measurements. We use this method to provide real-time measurements of copper during a Fenton-like reaction. Unlike with other chemical fluorescent probes, we can determine both the increase and decrease in copper formed in real time. Full article
(This article belongs to the Topic Advanced Nanomaterials for Sensing Applications)
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18 pages, 8236 KiB  
Article
Electrochemical Synthesis of Reduced Graphene Oxide/Gold Nanoparticles in a Single Step for Carbaryl Detection in Water
by Ibtihaj Albalawi, Hanan Alatawi, Samia Alsefri and Eric Moore
Sensors 2022, 22(14), 5251; https://doi.org/10.3390/s22145251 - 13 Jul 2022
Cited by 13 | Viewed by 3262
Abstract
In this study, an in situ synthesis approach based on electrochemical reduction and ion exchange was employed to detect carbaryl species using a disposable, screen-printed carbon electrode fabricated with nanocomposite materials. Reduced graphene oxide (rGO) was used to create a larger electrode surface [...] Read more.
In this study, an in situ synthesis approach based on electrochemical reduction and ion exchange was employed to detect carbaryl species using a disposable, screen-printed carbon electrode fabricated with nanocomposite materials. Reduced graphene oxide (rGO) was used to create a larger electrode surface and more active sites. Gold nanoparticles (AuNPs,) were incorporated to accelerate electron transfer and enhance sensitivity. A cation exchange Nafion polymer was used to enable the adhesion of rGO and AuNPs to the electrode surface and speed up ion exchange. Cyclic voltammetry (CV), energy dispersive X-ray spectroscopy (EDX), X-ray photoelectron spectroscopy (XPS), electrical impedance spectroscopy (EIS), atomic force microscopy (AFM) and scanning electron microscopy (SEM) were performed to study the electrochemical and physical properties of the modified sensor. In the presence of differential pulse voltammetry (DPV), an rGO/AuNP/Nafion-modified electrode was effectively used to measure the carbaryl concentration in river and tap water samples. The developed sensor exhibited superior electrochemical performance in terms of reproducibility, stability, efficiency and selectivity for carbaryl detection with a detection limit of 0.2 µM and a concentration range between 0.5µM and 250 µM. The proposed approach was compared to capillary electrophoresis with ultraviolet detection (CE-UV). Full article
(This article belongs to the Topic Advanced Nanomaterials for Sensing Applications)
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11 pages, 2239 KiB  
Article
Temperature Detectable Surface Coating with Carbon Nanotube/Epoxy Composites
by Seung-Jun Lee, Yu-Jin Jung, JeeWoong Park and Sung-Hwan Jang
Nanomaterials 2022, 12(14), 2369; https://doi.org/10.3390/nano12142369 - 11 Jul 2022
Cited by 6 | Viewed by 2506
Abstract
In the construction and machinery industry, heat is a major factor causing damage and destruction. The safety and efficiency of most machines and structures are greatly affected by temperature, and temperature management and control are essential. In this study, a carbon nanotube (CNT) [...] Read more.
In the construction and machinery industry, heat is a major factor causing damage and destruction. The safety and efficiency of most machines and structures are greatly affected by temperature, and temperature management and control are essential. In this study, a carbon nanotube (CNT) based temperature sensing coating that can be applied to machines and structures having various structural types was fabricated, and characteristics analysis and temperature sensing performance were evaluated. The surface coating, which detects temperature through resistance change is made of a nanocomposite composed of carbon nanotubes (CNT) and epoxy (EP). We investigated the electrical properties by CNT concentration and temperature sensing performance of CNT/EP coating against static and cyclic temperatures. In addition, the applicability of the CNT/EP coating was investigated through a partially heating and cooling experiment. As a result of the experiment, the CNT/EP coating showed higher electrical conductivity as the CNT concentration increased. In addition, the CNT/EP coating exhibits high sensing performance in the high and sub−zero temperature ranges with a negative temperature coefficient of resistance. Therefore, the proposed CNT/EP coatings are promising for use as multi-functional coating materials for the detection of high and freezing temperatures. Full article
(This article belongs to the Topic Advanced Nanomaterials for Sensing Applications)
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15 pages, 4777 KiB  
Article
Hierarchical Nanocomposites Electrospun Carbon NanoFibers/Carbon Nanotubes as a Structural Element of Potentiometric Sensors
by Barbara Niemiec, Marcel Zambrzycki, Robert Piech, Cecylia Wardak and Beata Paczosa-Bator
Materials 2022, 15(14), 4803; https://doi.org/10.3390/ma15144803 - 9 Jul 2022
Cited by 4 | Viewed by 1844
Abstract
This work proposes new carbon materials for intermediate layers in solid-contact electrodes sensitive for potassium ions. The group of tested materials includes electrospun carbon nanofibers, electrospun carbon nanofibers with incorporated cobalt nanoparticles and hierarchical nanocomposites composed of carbon nanotubes deposited on nanofibers with [...] Read more.
This work proposes new carbon materials for intermediate layers in solid-contact electrodes sensitive for potassium ions. The group of tested materials includes electrospun carbon nanofibers, electrospun carbon nanofibers with incorporated cobalt nanoparticles and hierarchical nanocomposites composed of carbon nanotubes deposited on nanofibers with different metal nanoparticles (cobalt or nickel) and nanotube density (high or low). Materials were characterized using scanning electron microscopy and contact angle microscopy. Electrical parameters of ready-to-use electrodes were characterized using chronopotentiometry and electrochemical impedance spectroscopy. The best results were obtained for potassium electrodes with carbon nanofibers with nickel-cobalt nanoparticles and high density of nanotubes layer: the highest capacity value (330 µF), the lowest detection limit (10−6.3 M), the widest linear range (10−6–10−1) and the best reproducibility of normal potential (0.9 mV). On the other hand the best potential reversibility, the lowest potential drift (20 μV·h−1) in the long-term test and the best hydrophobicity (contact angle 168°) were obtained for electrode with carbon nanofibers with cobalt nanoparticles and high density of carbon nanotubes. The proposed electrodes can be used successfully in potassium analysis of real samples as shown in the example of tomato juices. Full article
(This article belongs to the Topic Advanced Nanomaterials for Sensing Applications)
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13 pages, 1443 KiB  
Article
Impact of Helium Ion Implantation Dose and Annealing on Dense Near-Surface Layers of NV Centers
by Andris Berzins, Hugo Grube, Einars Sprugis, Guntars Vaivars and Ilja Fescenko
Nanomaterials 2022, 12(13), 2234; https://doi.org/10.3390/nano12132234 - 29 Jun 2022
Cited by 5 | Viewed by 2556
Abstract
The implantation of diamonds with helium ions has become a common method to create hundreds-nanometers-thick near-surface layers of NV centers for high-sensitivity sensing and imaging applications; however, optimal implantation dose and annealing temperature are still a matter of discussion. In this study, we [...] Read more.
The implantation of diamonds with helium ions has become a common method to create hundreds-nanometers-thick near-surface layers of NV centers for high-sensitivity sensing and imaging applications; however, optimal implantation dose and annealing temperature are still a matter of discussion. In this study, we irradiated HPHT diamonds with an initial nitrogen concentration of 100 ppm using different implantation doses of helium ions to create 200-nm thick NV layers. We compare a previously considered optimal implantation dose of ∼1012 He+/cm2 to double and triple doses by measuring fluorescence intensity, contrast, and linewidth of magnetic resonances, as well as longitudinal and transversal relaxation times T1 and T2. From these direct measurements, we also estimate concentrations of P1 and NV centers. In addition, we compare the three diamond samples that underwent three consequent annealing steps to quantify the impact of processing at 1100 °C, which follows initial annealing at 800 °C. By tripling the implantation dose, we have increased the magnetic sensitivity of our sensors by 28±5%. By projecting our results to higher implantation doses, we demonstrate that it is possible to achieve a further improvement of up to 70%. At the same time, additional annealing steps at 1100 °C improve the sensitivity only by 6.6 ± 2.7%. Full article
(This article belongs to the Topic Advanced Nanomaterials for Sensing Applications)
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8 pages, 1629 KiB  
Communication
Utilizing the Transverse Thermoelectric Effect of Thin Films for Pulse Laser Detection
by Yanju Sun, Haorong Wu, Lan Yu, Hui Sun, Peng Zhang, Xiaowei Zhang, Bo Dai and Yong Wang
Sensors 2022, 22(13), 4867; https://doi.org/10.3390/s22134867 - 28 Jun 2022
Cited by 10 | Viewed by 2106
Abstract
In this work, pulse laser detectors based on the transverse thermoelectric effect of YBa2Cu3O7-δ thin films on vicinal cut LaAlO3 (001) substrates have been fabricated. The anisotropic Seebeck coefficients between ab-plane (Sab) and [...] Read more.
In this work, pulse laser detectors based on the transverse thermoelectric effect of YBa2Cu3O7-δ thin films on vicinal cut LaAlO3 (001) substrates have been fabricated. The anisotropic Seebeck coefficients between ab-plane (Sab) and c-axis (Sc) of thin films are utilized to generate the output voltage signal in such kind of detectors. Fast response has been determined in these sensors, including both the rise time and the decay time. Under the irradiation of pulse laser with the pulse duration of 5–7 ns, the output voltage of these detectors shows the rise time and the decay time of 6 and 42 ns, respectively, which are much smaller than those from other materials. The small rise time in YBa2Cu3O7-δ-based detectors may be due to its low resistivity. While the high thermal conductivity and the large contribution of electronic thermal conductivity to the thermal conductivity of YBa2Cu3O7-δ are thought to be responsible for the small decay time. In addition, these detectors show good response under the irradiation of pulse lasers with a repetition rate of 4 kHz, including the precise determinations of amplitude and time. These results may pave a simple and convenient approach to manufacture the pulse laser detectors with a fast response. Full article
(This article belongs to the Topic Advanced Nanomaterials for Sensing Applications)
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12 pages, 2001 KiB  
Article
Perovskite-Based Memristor with 50-Fold Switchable Photosensitivity for In-Sensor Computing Neural Network
by Qilai Chen, Tingting Han, Jianmin Zeng, Zhilong He, Yulin Liu, Jinglin Sun, Minghua Tang, Zhang Zhang, Pingqi Gao and Gang Liu
Nanomaterials 2022, 12(13), 2217; https://doi.org/10.3390/nano12132217 - 28 Jun 2022
Cited by 10 | Viewed by 3004
Abstract
In-sensor computing can simultaneously output image information and recognition results through in-situ visual signal processing, which can greatly improve the efficiency of machine vision. However, in-sensor computing is challenging due to the requirement to controllably adjust the sensor’s photosensitivity. Herein, it is demonstrated [...] Read more.
In-sensor computing can simultaneously output image information and recognition results through in-situ visual signal processing, which can greatly improve the efficiency of machine vision. However, in-sensor computing is challenging due to the requirement to controllably adjust the sensor’s photosensitivity. Herein, it is demonstrated a ternary cationic halide Cs0.05FA0.81MA0.14 Pb(I0.85Br0.15)3 (CsFAMA) perovskite, whose External quantum efficiency (EQE) value is above 80% in the entire visible region (400–750 nm), and peak responsibility value at 750 nm reaches 0.45 A/W. In addition, the device can achieve a 50-fold enhancement of the photoresponsibility under the same illumination by adjusting the internal ion migration and readout voltage. A proof-of-concept visually enhanced neural network system is demonstrated through the switchable photosensitivity of the perovskite sensor array, which can simultaneously optimize imaging and recognition results and improve object recognition accuracy by 17% in low-light environments. Full article
(This article belongs to the Topic Advanced Nanomaterials for Sensing Applications)
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12 pages, 4181 KiB  
Article
The Aggregation of Destabilized Ag Triangular Nanoplates and Its Application in Detection of Thiram Residues
by Chunhong Zhang, Hao Ren, Xiangkui Jiang, Guangfeng Jia, Zhigang Pan and Yongchun Liu
Nanomaterials 2022, 12(13), 2152; https://doi.org/10.3390/nano12132152 - 23 Jun 2022
Cited by 4 | Viewed by 1755
Abstract
An aggregation or assembly of Ag triangular nanoplates (Ag TNPs) can cause dramatic changes in their optical properties, which is widely used in applications in the field of sensing. The assembly forms of nanoparticles are crucial for obtaining sensitive sensing signals, but it [...] Read more.
An aggregation or assembly of Ag triangular nanoplates (Ag TNPs) can cause dramatic changes in their optical properties, which is widely used in applications in the field of sensing. The assembly forms of nanoparticles are crucial for obtaining sensitive sensing signals, but it is unknown what kind of assembly dominates the aggregated Ag TNPs in aqueous solutions. Herein, using thiram-induced Ag TNP aggregation as a model, six different assembly models were established, including three planar (side-by-side, side-to-tip, and tip-to-tip) assemblies and three tridimensional (plane-to-plane, plane-to-tip, and plane-to-side) assemblies. The corresponding optical properties were then investigated. Both theoretical and experimental findings indicate that three-dimensional assemblies, especially plane-to-plane assembly, dominate the Ag TNPs aggregation solution, causing a blue shift of the absorption spectrum. Analysis of charge distribution patterns in Ag TNPs indicates that such a blue shift is caused by the electrostatic repulsive force in plane-to-plane assembly. Thus, we propose a simple colorimetric method for thiram detection using Ag TNPs as an indicator. The method exhibits a selective and sensitive response to thiram with a limit of detection of 0.13 μM in the range of 0.2–0.5 μM, as well as excellent performance in real samples like wheat. Full article
(This article belongs to the Topic Advanced Nanomaterials for Sensing Applications)
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12 pages, 3605 KiB  
Article
Ultrasensitive Detection of COVID-19 Virus N Protein Based on p-Toluenesulfonyl Modified Fluorescent Microspheres Immunoassay
by Mao Mao, Feng Wu, Xueying Shi, Yulan Huang and Lan Ma
Biosensors 2022, 12(7), 437; https://doi.org/10.3390/bios12070437 - 22 Jun 2022
Cited by 9 | Viewed by 2676
Abstract
The pandemic of new coronary pneumonia caused by the COVID-19 virus continues to ravage the world. Large-scale population testing is the key to controlling infection and related mortality worldwide. Lateral flow immunochromatographic assay (LFIA) is fast, inexpensive, simple to operate, and easy to [...] Read more.
The pandemic of new coronary pneumonia caused by the COVID-19 virus continues to ravage the world. Large-scale population testing is the key to controlling infection and related mortality worldwide. Lateral flow immunochromatographic assay (LFIA) is fast, inexpensive, simple to operate, and easy to carry, very suitable for detection sites. This study developed a COVID-19 N protein detect strip based on p-toluenesulfonyl modified rare earth fluorescent microspheres. The p-toluenesulfonyl-activated nanomaterials provide reactive sulfonyl esters to covalently attach antibodies or other ligands containing primary amino or sulfhydryl groups to the nanomaterial surface. Antibodies are immobilized on these nanomaterials through the Fc region, which ensures optimal orientation of the antibody, thereby increasing the capture rate of the target analyte. The use of buffers with high ionic strength can promote hydrophobic binding; in addition, higher pH could promote the reactivity of the tosyl group. The detection limit of the prepared COVID-19 N protein strips can reach 0.01 ng/mL, so it has great application potential in large-scale population screening. Full article
(This article belongs to the Topic Advanced Nanomaterials for Sensing Applications)
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11 pages, 2855 KiB  
Article
Highly Sensitive, Stretchable Pressure Sensor Using Blue Laser Annealed CNTs
by Chanju Park, Munsu Choi, Suhui Lee, Hyunho Kim, Taeheon Lee, Mohammad Masum Billah, Byunglib Jung and Jin Jang
Nanomaterials 2022, 12(13), 2127; https://doi.org/10.3390/nano12132127 - 21 Jun 2022
Cited by 10 | Viewed by 2987
Abstract
A piezoresistive sensor is an essential component of wearable electronics that can detect resistance changes when pressure is applied. In general, microstructures of sensing layers have been adopted as an effective approach to enhance piezoresistive performance. However, the mold-casted microstructures typically have quite [...] Read more.
A piezoresistive sensor is an essential component of wearable electronics that can detect resistance changes when pressure is applied. In general, microstructures of sensing layers have been adopted as an effective approach to enhance piezoresistive performance. However, the mold-casted microstructures typically have quite a thick layer with dozens of microscales. In this paper, a carbon microstructure is formed by blue laser annealing (BLA) on a carbon nanotube (CNT) layer, which changes the surface morphology of CNTs into carbonaceous protrusions and increases its thickness more than four times compared to the as-deposited layer. Then, the pressure sensor is fabricated using a spin-coating of styrene–ethylene–butylene–styrene (SEBS) elastomer on the BLA CNTs layer. A 1.32 µm-thick pressure sensor exhibits a high sensitivity of 6.87 × 105 kPa−1, a wide sensing range of 278 Pa~40 kPa and a fast response/recovery time of 20 ms, respectively. The stability of the pressure sensor is demonstrated by the repeated loading and unloading of 20 kPa for 4000 cycles. The stretchable pressure sensor was also demonstrated using lateral CNT electrodes on SEBS surface, exhibiting stable pressure performance, with up to 20% stretching. Full article
(This article belongs to the Topic Advanced Nanomaterials for Sensing Applications)
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11 pages, 1635 KiB  
Article
Acrylamide Hydrogel-Modified Silicon Nanowire Field-Effect Transistors for pH Sensing
by Gangrong Li, Qianhui Wei, Shuhua Wei, Jing Zhang, Qingxi Jin, Guozhi Wang, Jiawei Hu, Yan Zhu, Yun Kong, Qingzhu Zhang, Hongbin Zhao, Feng Wei and Hailing Tu
Nanomaterials 2022, 12(12), 2070; https://doi.org/10.3390/nano12122070 - 16 Jun 2022
Cited by 6 | Viewed by 2499
Abstract
In this study, we report a pH-responsive hydrogel-modified silicon nanowire field-effect transistor for pH sensing, whose modification is operated by spin coating, and whose performance is characterized by the electrical curve of field-effect transistors. The results show that the hydrogel sensor can measure [...] Read more.
In this study, we report a pH-responsive hydrogel-modified silicon nanowire field-effect transistor for pH sensing, whose modification is operated by spin coating, and whose performance is characterized by the electrical curve of field-effect transistors. The results show that the hydrogel sensor can measure buffer pH in a repeatable and stable manner in the pH range of 3–13, with a high pH sensitivity of 100 mV/pH. It is considered that the swelling of hydrogel occurring in an aqueous solution varies the dielectric properties of acrylamide hydrogels, causing the abrupt increase in the source-drain current. It is believed that the design of the sensor can provide a promising direction for future biosensing applications utilizing the excellent biocompatibility of hydrogels. Full article
(This article belongs to the Topic Advanced Nanomaterials for Sensing Applications)
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21 pages, 4293 KiB  
Article
Synthesis of Vapochromic Dyes Having Sensing Properties for Vapor Phase of Organic Solvents Used in Semiconductor Manufacturing Processes and Their Application to Textile-Based Sensors
by Junheon Lee, Duyoung Kim and Taekyeong Kim
Sensors 2022, 22(12), 4487; https://doi.org/10.3390/s22124487 - 14 Jun 2022
Cited by 5 | Viewed by 1902
Abstract
Two vapochromic dyes (DMx and DM) were synthesized to be used for textile-based sensors detecting the vapor phase of organic solvents. They were designed to show sensitive color change properties at a low concentration of vapors at room temperature. They were applied to [...] Read more.
Two vapochromic dyes (DMx and DM) were synthesized to be used for textile-based sensors detecting the vapor phase of organic solvents. They were designed to show sensitive color change properties at a low concentration of vapors at room temperature. They were applied to cotton fabrics as a substrate of the textile-based sensors to examine their sensing properties for nine organic solvents frequently used in semiconductor manufacturing processes, such as trichloroethylene, dimethylacetamide, iso-propanol, methanol, n-hexane, ethylacetate, benzene, acetone, and hexamethyldisilazane. The textile sensor exhibited strong sensing properties of polar solvents rather than non-polar solvents. In particular, the detection of dimethylacetamide was the best, showing a color difference of 15.9 for DMx and 26.2 for DM under 300 ppm exposure. Even at the low concentration of 10 ppm of dimethylacetamide, the color change values reached 7.7 and 13.6, respectively, in an hour. The maximum absorption wavelength of the textile sensor was shifted from 580 nm to 550 nm for DMx and 550 nm to 540 nm for DM, respectively, due to dimethylacetamide exposure. The sensing mechanism was considered to depend on solvatochromism, the aggregational properties of the dyes and the adsorption amounts of the solvent vapors on the textile substrates to which the dyes were applied. Finally, the reusability of the textile sensor was tested for 10 cycles. Full article
(This article belongs to the Topic Advanced Nanomaterials for Sensing Applications)
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15 pages, 4761 KiB  
Article
One-Step Co-Electrodeposition of Copper Nanoparticles-Chitosan Film-Carbon Nanoparticles-Multiwalled Carbon Nanotubes Composite for Electroanalysis of Indole-3-Acetic Acid and Salicylic Acid
by Yiwen Kuang, Mengxue Li, Shiyu Hu, Lu Yang, Zhanning Liang, Jiaqi Wang, Hongmei Jiang, Xiaoyun Zhou and Zhaohong Su
Sensors 2022, 22(12), 4476; https://doi.org/10.3390/s22124476 - 13 Jun 2022
Cited by 11 | Viewed by 3359
Abstract
A sensitive simultaneous electroanalysis of phytohormones indole-3-acetic acid (IAA) and salicylic acid (SA) based on a novel copper nanoparticles-chitosan film-carbon nanoparticles-multiwalled carbon nanotubes (CuNPs-CSF-CNPs-MWCNTs) composite was reported. CNPs were prepared by hydrothermal reaction of chitosan. Then the CuNPs-CSF-CNPs-MWCNTs composite was facilely prepared by [...] Read more.
A sensitive simultaneous electroanalysis of phytohormones indole-3-acetic acid (IAA) and salicylic acid (SA) based on a novel copper nanoparticles-chitosan film-carbon nanoparticles-multiwalled carbon nanotubes (CuNPs-CSF-CNPs-MWCNTs) composite was reported. CNPs were prepared by hydrothermal reaction of chitosan. Then the CuNPs-CSF-CNPs-MWCNTs composite was facilely prepared by one-step co-electrodeposition of CuNPs and CNPs fixed chitosan residues on modified electrode. Scanning electron microscope (SEM), transmission electron microscopy (TEM), selected area electron diffraction (SAED), energy dispersive spectroscopy (EDS), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), and linear sweep voltammetry (LSV) were used to characterize the properties of the composite. Under optimal conditions, the composite modified electrode had a good linear relationship with IAA in the range of 0.01–50 μM, and a good linear relationship with SA in the range of 4–30 μM. The detection limits were 0.0086 μM and 0.7 μM (S/N = 3), respectively. In addition, the sensor could also be used for the simultaneous detection of IAA and SA in real leaf samples with satisfactory recovery. Full article
(This article belongs to the Topic Advanced Nanomaterials for Sensing Applications)
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9 pages, 2160 KiB  
Article
Detection of DNA Methyltransferase Activity via Fluorescence Resonance Energy Transfer and Exonuclease-Mediated Target Recycling
by Tingting Hu, Changbei Ma, Ying Yan and Junxiang Chen
Biosensors 2022, 12(6), 395; https://doi.org/10.3390/bios12060395 - 8 Jun 2022
Cited by 3 | Viewed by 2235
Abstract
In this study, a sensitive method for detecting DNA methyltransferase (MTase) activity was developed by combining the effective fluorescence resonance energy transfer (FRET) of cationic conjugated polymers and exonuclease (Exo) III–mediated signal amplification. DNA adenine MTase targets the GATC sequence within a substrate [...] Read more.
In this study, a sensitive method for detecting DNA methyltransferase (MTase) activity was developed by combining the effective fluorescence resonance energy transfer (FRET) of cationic conjugated polymers and exonuclease (Exo) III–mediated signal amplification. DNA adenine MTase targets the GATC sequence within a substrate and converts the adenine in this sequence into N6-methyladenine. In the method developed in this study, the methylated substrate is cleaved using Dpn I, whereby a single-stranded oligodeoxynucleotide (oligo) is released. Afterward, the oligo is hybridized to the 3ʹ protruding end of the F-DNA probe to form a double-stranded DNA, which is then digested by Exo III. Subsequently, due to weak electrostatic interactions, only a weak FRET signal is observed. The introduction of the Exo-III–mediated target-recycling reaction improved the sensitivity for detecting MTase. This detection method was found to be sensitive for MTase detection, with the lowest detection limit of 0.045 U/mL, and was also suitable for MTase-inhibitor screening, whereby such inhibitors can be identified for disease treatment. Full article
(This article belongs to the Topic Advanced Nanomaterials for Sensing Applications)
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13 pages, 4936 KiB  
Article
Facile Fabrication of Graphene Oxide Nanoribbon-Based Nanocomposite Papers with Different Oxidation Degrees and Morphologies for Tunable Fire-Warning Response
by Wei-Wei Qiu, Zhi-Ran Yu, Ling-Yun Zhou, Ling-Yu Lv, Heng Chen and Long-Cheng Tang
Nanomaterials 2022, 12(12), 1963; https://doi.org/10.3390/nano12121963 - 8 Jun 2022
Cited by 8 | Viewed by 2137
Abstract
Smart fire-warning sensors based on graphene oxide (GO) nanomaterials, via monitoring their temperature-responsive resistance transition, have attracted considerable interest for several years. However, an important question remains as to whether or not different oxidation degrees of the GO network can produce different impacts [...] Read more.
Smart fire-warning sensors based on graphene oxide (GO) nanomaterials, via monitoring their temperature-responsive resistance transition, have attracted considerable interest for several years. However, an important question remains as to whether or not different oxidation degrees of the GO network can produce different impacts on fire-warning responses. In this study, we synthesized three types of GO nanoribbons (GONRs) with different oxidation degrees and morphologies, and thus prepared flame retardant polyethylene glycol (PEG)/GONR/montmorillonite (MMT) nanocomposite papers via a facile, solvent free, and low-temperature evaporation-induced assembly approach. The results showed that the presence of the GONRs in the PEG/MMT promoted the formation of an interconnected nacre-like layered structure, and that appropriate oxidation of the GONRs provided better reinforcing efficiency and lower creep deformation. Furthermore, the different oxidation degrees of the GONRs produced a tunable flame-detection response, and an ideal fire-warning signal in pre-combustion (e.g., 3, 18, and 33 s at 300 °C for the three PEG/GONR/MMT nanocomposite papers), superior to the previous GONR-based fire-warning materials. Clearly, this work provides a novel strategy for the design and development of smart fire-warning sensors. Full article
(This article belongs to the Topic Advanced Nanomaterials for Sensing Applications)
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14 pages, 2700 KiB  
Article
Magnetic Halloysite Nanotube-Based SERS Biosensor Enhanced with Au@Ag Core–Shell Nanotags for Bisphenol A Determination
by Sen Li, Defu He, Shuning Li, Ruipeng Chen, Yuan Peng, Shuang Li, Dianpeng Han, Yu Wang, Kang Qin, Shuyue Ren, Ping Chen and Zhixian Gao
Biosensors 2022, 12(6), 387; https://doi.org/10.3390/bios12060387 - 2 Jun 2022
Cited by 6 | Viewed by 2811
Abstract
Bisphenol A (BPA) has emerged as a contaminant of concern because long-term exposure may affect the human endocrine system. Herein, a novel aptamer sensor based on magnetic separation and surface-enhanced Raman scattering (SERS) is proposed for the extremely sensitive and specific detection of [...] Read more.
Bisphenol A (BPA) has emerged as a contaminant of concern because long-term exposure may affect the human endocrine system. Herein, a novel aptamer sensor based on magnetic separation and surface-enhanced Raman scattering (SERS) is proposed for the extremely sensitive and specific detection of trace BPA. Moreover, the capture unit was prepared by immobilizing thiolated (SH)-BPA aptamer complementary DNA on AuNP-coated magnetic halloysite nanotubes (MNTs@AuNPs), and SH-BPA aptamer-modified Au@4-MBA@Ag core–shell SERS nanotags acted as signal units. By the complementary pairing of the BPA aptamer and the corresponding DNA, MNTs@AuNPs and Au@4-MBA@AgCS were linked together through hybridization-ligation, which acted as the SERS substrate. In the absence of BPA, the constructed aptamer sensor generated electromagnetic enhancement and plasmon coupling to improve the sensitivity of SERS substrates. Owing to the high affinity between BPA and the aptamer, the aptamer probe bound to BPA was separated from the capture unit by an externally-induced magnetic field. Thus, the Raman intensity of the MNTs@AuNP-Ag@AuCS core–satellite assemblies was negatively correlated with the BPA concentration. High sensitivity measurements of BPA might be performed by determining the decline in SERS signal strength together with concentration variations. The proposed aptasensor is a promising biosensing platform for BPA detection. Full article
(This article belongs to the Topic Advanced Nanomaterials for Sensing Applications)
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12 pages, 7805 KiB  
Article
Fluorescent Oxygen-Doped g-C3N4 Quantum Dots for Selective Detection Fe3+ Ions in Cell Imaging
by Jiahui Zhang, Yan Jing, Peng Zhang and Benhua Xu
Nanomaterials 2022, 12(11), 1826; https://doi.org/10.3390/nano12111826 - 26 May 2022
Cited by 11 | Viewed by 2326
Abstract
Herein, oxygen-doped g-C3N4 quantum dots (OCNQDs) were fabricated through sintering and ultrasonic-assisted liquid-phase exfoliation methods. The obtained OCNQDs with uniform size show high crystalline quality, and the average diameter is 6.7 ± 0.5 nm. Furthermore, the OCNQDs display excellent fluorescence [...] Read more.
Herein, oxygen-doped g-C3N4 quantum dots (OCNQDs) were fabricated through sintering and ultrasonic-assisted liquid-phase exfoliation methods. The obtained OCNQDs with uniform size show high crystalline quality, and the average diameter is 6.7 ± 0.5 nm. Furthermore, the OCNQDs display excellent fluorescence properties, good water solubility, and excellent photo stability. The OCNQDs as fluorescence probe show high sensitivity and selectivity to Fe3+ ions. Furthermore, the fluorescent OCNQDs are applied for live cell imaging and Fe3+ ions detecting in living cells with low cytotoxicity, good biocompatibility, and high permeability. Overall, the fluorescent OCNQDs fabricated in this work can be promising candidates for a range of chemical sensors and bioimaging applications. Full article
(This article belongs to the Topic Advanced Nanomaterials for Sensing Applications)
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13 pages, 5056 KiB  
Article
Integrated Multifunctional Graphene Discs 2D Plasmonic Optical Tweezers for Manipulating Nanoparticles
by Hongyan Yang, Ziyang Mei, Zhenkai Li, Houquan Liu, Hongchang Deng, Gongli Xiao, Jianqing Li, Yunhan Luo and Libo Yuan
Nanomaterials 2022, 12(10), 1769; https://doi.org/10.3390/nano12101769 - 23 May 2022
Cited by 3 | Viewed by 3392
Abstract
Optical tweezers are key tools to trap and manipulate nanoparticles in a non-invasive way, and have been widely used in the biological and medical fields. We present an integrated multifunctional 2D plasmonic optical tweezer consisting of an array of graphene discs and the [...] Read more.
Optical tweezers are key tools to trap and manipulate nanoparticles in a non-invasive way, and have been widely used in the biological and medical fields. We present an integrated multifunctional 2D plasmonic optical tweezer consisting of an array of graphene discs and the substrate circuit. The substrate circuit allows us to apply a bias voltage to configure the Fermi energy of graphene discs independently. Our work is based on numerical simulation of the finite element method. Numerical results show that the optical force is generated due to the localized surface plasmonic resonance (LSPR) mode of the graphene discs with Fermi Energy Ef = 0.6 eV under incident intensity I = 1 mW/μm2, which has a very low incident intensity compared to other plasmonic tweezers systems. The optical forces on the nanoparticles can be controlled by modulating the position of LSPR excitation. Controlling the position of LSPR excitation by bias voltage gates to configure the Fermi energy of graphene disks, the nanoparticles can be dynamically transported to arbitrary positions in the 2D plane. Our work is integrated and has multiple functions, which can be applied to trap, transport, sort, and fuse nanoparticles independently. It has potential applications in many fields, such as lab-on-a-chip, nano assembly, enhanced Raman sensing, etc. Full article
(This article belongs to the Topic Advanced Nanomaterials for Sensing Applications)
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11 pages, 1845 KiB  
Article
Gold Ion Beam Milled Gold Zero-Mode Waveguides
by Troy C. Messina, Bernadeta R. Srijanto, Charles Patrick Collier, Ivan I. Kravchenko and Christopher I. Richards
Nanomaterials 2022, 12(10), 1755; https://doi.org/10.3390/nano12101755 - 21 May 2022
Cited by 2 | Viewed by 2392
Abstract
Zero-mode waveguides (ZMWs) are widely used in single molecule fluorescence microscopy for their enhancement of emitted light and the ability to study samples at physiological concentrations. ZMWs are typically produced using photo or electron beam lithography. We report a new method of ZMW [...] Read more.
Zero-mode waveguides (ZMWs) are widely used in single molecule fluorescence microscopy for their enhancement of emitted light and the ability to study samples at physiological concentrations. ZMWs are typically produced using photo or electron beam lithography. We report a new method of ZMW production using focused ion beam (FIB) milling with gold ions. We demonstrate that ion-milled gold ZMWs with 200 nm apertures exhibit similar plasmon-enhanced fluorescence seen with ZMWs fabricated with traditional techniques such as electron beam lithography. Full article
(This article belongs to the Topic Advanced Nanomaterials for Sensing Applications)
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14 pages, 3152 KiB  
Article
RT-LAMP-Based Molecular Diagnostic Set-Up for Rapid Hepatitis C Virus Testing
by Sandhya Sharma, Emmanuel Thomas, Massimo Caputi and Waseem Asghar
Biosensors 2022, 12(5), 298; https://doi.org/10.3390/bios12050298 - 5 May 2022
Cited by 15 | Viewed by 4983
Abstract
Hepatitis C virus (HCV) infections occur in approximately 3% of the world population. The development of an enhanced and extensive-scale screening is required to accomplish the World Health Organization’s (WHO) goal of eliminating HCV as a public health problem by 2030. However, standard [...] Read more.
Hepatitis C virus (HCV) infections occur in approximately 3% of the world population. The development of an enhanced and extensive-scale screening is required to accomplish the World Health Organization’s (WHO) goal of eliminating HCV as a public health problem by 2030. However, standard testing methods are time-consuming, expensive, and challenging to deploy in remote and underdeveloped areas. Therefore, a cost-effective, rapid, and accurate point-of-care (POC) diagnostic test is needed to properly manage the disease and reduce the economic burden caused by high case numbers. Herein, we present a fully automated reverse-transcription loop-mediated isothermal amplification (RT-LAMP)-based molecular diagnostic set-up for rapid HCV detection. The set-up consists of an automated disposable microfluidic chip, a small surface heater, and a reusable magnetic actuation platform. The microfluidic chip contains multiple chambers in which the plasma sample is processed. The system utilizes SYBR green dye to detect the amplification product with the naked eye. The efficiency of the microfluidic chip was tested with human plasma samples spiked with HCV virions, and the limit of detection observed was 500 virions/mL within 45 min. The entire virus detection process was executed inside a uniquely designed, inexpensive, disposable, and self-driven microfluidic chip with high sensitivity and specificity. Full article
(This article belongs to the Topic Advanced Nanomaterials for Sensing Applications)
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14 pages, 3074 KiB  
Article
Molecularly Imprinted Polymer-Amyloid Fibril-Based Electrochemical Biosensor for Ultrasensitive Detection of Tryptophan
by Ibrar Alam, Benchaporn Lertanantawong, Thana Sutthibutpong, Primana Punnakitikashem and Piyapong Asanithi
Biosensors 2022, 12(5), 291; https://doi.org/10.3390/bios12050291 - 2 May 2022
Cited by 6 | Viewed by 3439
Abstract
A tryptophan (Trp) sensor was investigated based on electrochemical impedance spectroscopy (EIS) of a molecularly imprinted polymer on a lysozyme amyloid fibril (MIP-AF). The MIP-AF was composed of aniline as a monomer chemically polymerized in the presence of a Trp template molecule onto [...] Read more.
A tryptophan (Trp) sensor was investigated based on electrochemical impedance spectroscopy (EIS) of a molecularly imprinted polymer on a lysozyme amyloid fibril (MIP-AF). The MIP-AF was composed of aniline as a monomer chemically polymerized in the presence of a Trp template molecule onto the AF surface. After extracting the template molecule, the MIP-AF had cavities with a high affinity for the Trp molecules. The obtained MIP-AF demonstrated rapid Trp adsorption and substantial binding capacity (50 µM mg−1). Trp determination was studied using non-Faradaic EIS by drop drying the MIP-AF on the working electrode of a screen-printed electrode. The MIP-AF provided a large linear range (10 pM–80 µM), a low detection limit (8 pM), and high selectivity for Trp determination. Furthermore, the proposed method also indicates that the MIP-AF can be used to determine Trp in real samples such as milk and cancer cell media. Full article
(This article belongs to the Topic Advanced Nanomaterials for Sensing Applications)
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12 pages, 3174 KiB  
Article
Integrated CuO/Pd Nanospike Hydrogen Sensor on Silicon Substrate
by Ru Lin, Qi Hu, Zuolian Liu, Shusheng Pan, Zhifeng Chen, Wei Zhang, Zhiyu Liu, Shaolin Zhang and Chengyun Zhang
Nanomaterials 2022, 12(9), 1533; https://doi.org/10.3390/nano12091533 - 2 May 2022
Cited by 9 | Viewed by 2888
Abstract
A large area of randomly distributed nanospike as nanostructured template was induced by femtosecond (fs) laser on a silicon substrate in water. Copper oxide (CuO) and palladium (Pd) heterostructured nanofilm were coated on the nanospikes by magnetron sputtering technology and vacuum thermal evaporation [...] Read more.
A large area of randomly distributed nanospike as nanostructured template was induced by femtosecond (fs) laser on a silicon substrate in water. Copper oxide (CuO) and palladium (Pd) heterostructured nanofilm were coated on the nanospikes by magnetron sputtering technology and vacuum thermal evaporation coating technology respectively for the construction of a p-type hydrogen sensor. Compared with the conventional gas sensor based on CuO working at high temperature, nanostructured CuO/Pd heterostructure exhibited promising detection capability to hydrogen at room temperature. The detection sensitivity to 1% H2 was 10.8%, the response time was 198 s, and the detection limit was as low as 40 ppm, presenting an important application prospect in the clean energy field. The excellent reusability and selectivity of the CuO/Pd heterostructure sensor toward H2 at room temperature were also demonstrated by a series of cyclic response characteristics. It is believed that our room-temperature hydrogen sensor fabricated with a waste-free green process, directly on silicon substrate, would greatly promote the future fabrication of a circuit-chip integrating hydrogen sensor. Full article
(This article belongs to the Topic Advanced Nanomaterials for Sensing Applications)
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22 pages, 5494 KiB  
Article
The Auto-Combustion Method Synthesized Eu2O3- ZnO Nanostructured Composites for Electronic and Photocatalytic Applications
by Thekrayat H. AlAbdulaal, Vanga Ganesh, Manal AlShadidi, Mai S. A. Hussien, Abdelfatteh Bouzidi, Hamed Algarni, Heba Y. Zahran, Mohamed Sh. Abdel-wahab, Ibrahim S. Yahia and Samia Nasr
Materials 2022, 15(9), 3257; https://doi.org/10.3390/ma15093257 - 1 May 2022
Cited by 19 | Viewed by 2213
Abstract
An efficient and environmentally friendly combustion technique was employed to produce ZnO nanopowders with different Eu concentrations (from 0.001 g to 5 g). The structural morphology of the Eu2O3-ZnO nanocomposites was examined using XRD, SEM, and infrared spectroscopy (FT-IR). [...] Read more.
An efficient and environmentally friendly combustion technique was employed to produce ZnO nanopowders with different Eu concentrations (from 0.001 g to 5 g). The structural morphology of the Eu2O3-ZnO nanocomposites was examined using XRD, SEM, and infrared spectroscopy (FT-IR). In addition, UV-Vis diffuse reflectance spectroscopy was also used to investigate the effects of europium (Eu) dopant on the optical behaviors and energy bandgaps of nano-complex oxides. The photocatalytic degradation efficiency of phenol and methylene blue was investigated using all the prepared Eu2O3-ZnO nanostructured samples. Photocatalytic effectiveness increased when europium (Eu) doping ratios increased. After adding moderate Eu, more hydroxyl radicals were generated over ZnO. The best photocatalyst for phenol degradation was 1 percent Eu2O3-ZnO, while it was 0.5 percent Eu2O3-ZnO for methylene blue solutions. The obtained Eu2O3-doped ZnO nanostructured materials are considered innovative, promising candidates for a wide range of nano-applications, including biomedical and photocatalytic degradation of organic dyes and phenol. Full article
(This article belongs to the Topic Advanced Nanomaterials for Sensing Applications)
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23 pages, 5352 KiB  
Article
Tyrosinase-Based Biosensor—A New Tool for Chlorogenic Acid Detection in Nutraceutical Formulations
by Irina Georgiana Munteanu and Constantin Apetrei
Materials 2022, 15(9), 3221; https://doi.org/10.3390/ma15093221 - 29 Apr 2022
Cited by 15 | Viewed by 2639
Abstract
The purpose of our research was to develop a new enzymatic biosensor, GPH-MnPc-Tyr/SPE, using as a support screen-printed carbon electrode (SPE) modified with graphene, manganese phthalocyanine, and tyrosinase, with the aim of developing sensitive detection of chlorogenic acid (CGA). To immobilise tyrosinase on [...] Read more.
The purpose of our research was to develop a new enzymatic biosensor, GPH-MnPc-Tyr/SPE, using as a support screen-printed carbon electrode (SPE) modified with graphene, manganese phthalocyanine, and tyrosinase, with the aim of developing sensitive detection of chlorogenic acid (CGA). To immobilise tyrosinase on the sensor surface, crosslinking with the glutaraldehyde technique was used, thus increasing the enzyme bioactivity on this electrode. The modified electrode has a great catalytic effect on the electrochemical redox of chlorogenic acid, compared to the simple, unmodified SPE. The peak current response of the biosensor for CGA was linear in the range of 0.1–10.48 μM, obtaining a calibration curve using cyclic voltammetry (CV) and square-wave voltammetry (SWV). Subsequently, the detection limit (LOD) and the quantification limit (LOQ) were determined, obtaining low values, i.e., LOD = 1.40 × 10−6 M; LOQ = 4.69 × 10−6 M by cyclic voltammetry and LOD = 2.32 × 10−7 M; LOQ = 7.74 × 10−7 M, by square-wave voltammetry (SWV). These results demonstrate that the method is suitable for the detection of CGA in nutraceutical formulations. Therefore, GPH-MnPc-Tyr/SPE was used for the quantitative determination of CGA in three products, by means of cyclic voltammetry. The Folin–Ciocalteu spectrophotometric assay was used for the validation of the results, obtaining a good correlation between the voltammetric method and the spectrophotometric one, at a confidence level of 95%. Moreover, by means of the DPPH method, the antioxidant activity of the compound was determined, thus demonstrating the antioxidant effect of CGA in all nutraceuticals studied. Full article
(This article belongs to the Topic Advanced Nanomaterials for Sensing Applications)
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15 pages, 5377 KiB  
Article
Bio-Inspired Mechano-Sensor Based on the Deformation of Slit Wake
by Kejun Wang, Lei Gao, Yuecheng Gui, Zezhong Lu, Deshan Wang, Jiaqiang Li and Qian Wang
Appl. Sci. 2022, 12(9), 4456; https://doi.org/10.3390/app12094456 - 28 Apr 2022
Cited by 2 | Viewed by 1942
Abstract
Internal mechano-sensors, as an indispensable part of the proprioceptive system of intelligent equipment, have attracted enormous research interest because of their extremely crucial role in monitoring machining processes, real-time diagnosis of equipment faults, adaptive motor control and so on. The mechano-sensory structure with [...] Read more.
Internal mechano-sensors, as an indispensable part of the proprioceptive system of intelligent equipment, have attracted enormous research interest because of their extremely crucial role in monitoring machining processes, real-time diagnosis of equipment faults, adaptive motor control and so on. The mechano-sensory structure with signal-transduction function is an important factor in determining the sensing performance of a mechano-sensor. However, contrary to the wide application of the cantilever beam as the sensory structure of external mechano-sensors in order to guarantee their exteroceptive ability, there is still a lack of an effective and widely used sensory structure to significantly improve the sensing performance of internal mechano-sensors. Here, inspired by the scorpion using the specialized slit as the sensory structure of internal mechano-sensilla, the slit is ingeniously used in the design of the engineered internal mechano-sensor. In order to improve the deformability of the slit wake, the hollowed-out design around the slit tail of biological mechano-sensilla is researched. Meanwhile, to mimic the easily deformed flexible cuticular membrane covering the slit, the ultrathin, flexible, crack-based strain sensor is used as the sensing element to cover the controllable slit wake. Based on the coupling deformation of the slit wake, as well as the flexible strain sensor, the slit-based mechano-sensor shows excellent sensing performance to various mechanical signals such as displacement and vibration signals. Full article
(This article belongs to the Topic Advanced Nanomaterials for Sensing Applications)
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14 pages, 3621 KiB  
Article
Rapid Colorimetric pH-Responsive Gold Nanocomposite Hydrogels for Sensing Applications
by Ahmed E. Salih, Mohamed Elsherif, Fahad Alam, Matteo Chiesa and Haider Butt
Nanomaterials 2022, 12(9), 1486; https://doi.org/10.3390/nano12091486 - 27 Apr 2022
Cited by 7 | Viewed by 2547
Abstract
Surface functionalization of metallic nanoparticles (NPs) with external groups can be engineered to fabricate sensors that are responsive to various stimuli like temperature, pH, and numerous ions. Herein, we report the synthesis of gold nanoparticles (GNPs) functionalized with 3-mercaptopropionic acid (GNPs-MPA) and the [...] Read more.
Surface functionalization of metallic nanoparticles (NPs) with external groups can be engineered to fabricate sensors that are responsive to various stimuli like temperature, pH, and numerous ions. Herein, we report the synthesis of gold nanoparticles (GNPs) functionalized with 3-mercaptopropionic acid (GNPs-MPA) and the doping of these nanoparticles into hydrogel materials using the breathing-in/breathing-out (BI-BO) method. MPA has a carboxyl group that becomes protonated and, thus, ionized at a pH below its pKa (4.32); hence, the GNPs-MPA solutions and gels were mostly pH-responsive in the range of 3–5. Optical properties were assessed through ultraviolet-visible (UV-Vis) spectroscopy, namely: transmission and absorption, and the parameters used to quantify the pH changes were the full width at half maximum (FWHM) and position of surface plasmon resonance (SPR). The solutions and gels gradually changed their colors from red to indigo with pH decrementation from 5 to 3, respectively. Furthermore, the solutions’ and doped gels’ highest FWHM sensitivities towards pH variations were 20 nm and 55 nm, respectively, while the SPR’s position sensitivities were 18 nm and 10 nm, respectively. Also, transmission and scanning electron microscopy showed synchronized dispersion and aggregation of NPs with pH change in both solution and gel forms. The gel exhibited excellent repeatability and reversibility properties, and its response time was instantaneous, which makes its deployment as a colorimetric pH-triggered sensor practical. To the best of our knowledge, this is the first study that has incorporated GNPs into hydrogels utilizing the BI-BO method and demonstrated the pH-dependent optical and colorimetric properties of the developed nanocomposites. Full article
(This article belongs to the Topic Advanced Nanomaterials for Sensing Applications)
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14 pages, 3815 KiB  
Article
Design of a Highly Sensitive Reduced Graphene Oxide/Graphene Oxide@Cellulose Acetate/Thermoplastic Polyurethane Flexible Sensor
by Yujie Yang, Tan Yi, Yang Liu, Hui Zhao and Chen Liang
Sensors 2022, 22(9), 3281; https://doi.org/10.3390/s22093281 - 25 Apr 2022
Cited by 16 | Viewed by 2938
Abstract
As a substitute for rigid sensors, flexible sensing materials have been greatly developed in recent years, but maintaining the stability of conductive fillers and the stability of micro-strain sensing is still a major challenge. In this experiment, we innovatively prepared a polyurethane-based cellulose [...] Read more.
As a substitute for rigid sensors, flexible sensing materials have been greatly developed in recent years, but maintaining the stability of conductive fillers and the stability of micro-strain sensing is still a major challenge. In this experiment, we innovatively prepared a polyurethane-based cellulose acetate composite membrane (CA/TPU) with abundant mesopores through electrospinning. Then, we reduced graphene oxide (rGO)—as a conductive filler—and graphene oxide (GO)—as an insulating layer—which were successively and firmly anchored on the CA/TPU nanofiber membrane with the ultrasonic impregnation method, to obtain an rGO/GO@CA/TPU sensor with a GF of 3.006 under a very small strain of 0.5%. The flexibility of the film and its high sensitivity under extremely low strains enables the detection of subtle human motions (such as finger bending, joint motion, etc.), making it suitable for potential application in wearable electronic devices. Full article
(This article belongs to the Topic Advanced Nanomaterials for Sensing Applications)
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14 pages, 3931 KiB  
Article
Plasmonic Micro-Channel Assisted Photonic Crystal Fiber Based Highly Sensitive Sensor for Multi-Analyte Detection
by Q. M. Kamrunnahar, Firoz Haider, Rifat Ahmmed Aoni, Jannatul Robaiat Mou, Shamsuttiyeba Shifa, Feroza Begum, Hairul Azhar Abdul-Rashid and Rajib Ahmed
Nanomaterials 2022, 12(9), 1444; https://doi.org/10.3390/nano12091444 - 23 Apr 2022
Cited by 25 | Viewed by 2860
Abstract
A dual-channel propagation controlled photonic crystal fiber (PCF)-based plasmonic sensor was presented to detect multiple analytes simultaneously. Plasmonic micro-channels were placed on the outer surface of the PCF, which facilitates an easy sensing mechanism. The sensor was numerically investigated by the finite element [...] Read more.
A dual-channel propagation controlled photonic crystal fiber (PCF)-based plasmonic sensor was presented to detect multiple analytes simultaneously. Plasmonic micro-channels were placed on the outer surface of the PCF, which facilitates an easy sensing mechanism. The sensor was numerically investigated by the finite element method (FEM) with the perfectly matched layer (PML) boundary conditions. The proposed sensor performances were analyzed based on optimized sensor parameters, such as confinement loss, resonance coupling, resolution, sensitivity, and figure of merit (FOM). The proposed sensor showed a maximum wavelength sensitivity (WS) of 25,000 nm/refractive index unit (RIU) with a maximum sensor resolution (SR) of 4.0 × 10−6 RIU for channel 2 (Ch-2), and WS of 3000 nm/RIU with SR of 3.33 × 10−5 RIU for channel 1 (Ch-1). To the best of our knowledge, the proposed sensor exhibits the highest WS compared with the previously reported multi-analyte based PCF surface plasmon resonance (SPR) sensors. The proposed sensor could detect the unknown analytes within the refractive index (RI) range of 1.32 to 1.39 in the visible to near infrared region (550 to 1300 nm). In addition, the proposed sensor offers the maximum Figure of Merit (FOM) of 150 and 500 RIU−1 with the limit of detection (LOD) of 1.11 × 10−8 RIU2/nm and 1.6 × 10−10 RIU2/nm for Ch-1 and Ch-2, respectively. Due to its highly sensitive nature, the proposed multi-analyte PCF SPR sensor could be a prominent candidate in the field of biosensing to detect biomolecule interactions and chemical sensing. Full article
(This article belongs to the Topic Advanced Nanomaterials for Sensing Applications)
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12 pages, 2483 KiB  
Article
Plasmonic Azobenzene Chemoreporter for Surface-Enhanced Raman Scattering Detection of Biothiols
by Mariacristina Turino, Ramon A. Alvarez-Puebla and Luca Guerrini
Biosensors 2022, 12(5), 267; https://doi.org/10.3390/bios12050267 - 22 Apr 2022
Cited by 2 | Viewed by 2896
Abstract
Low molecular weight thiols (biothiols) are highly active compounds extensively involved in human physiology. Their abnormal levels have been associated with multiple diseases. In recent years, major efforts have been devoted to developing new nanosensing methods for the low cost and fast quantification [...] Read more.
Low molecular weight thiols (biothiols) are highly active compounds extensively involved in human physiology. Their abnormal levels have been associated with multiple diseases. In recent years, major efforts have been devoted to developing new nanosensing methods for the low cost and fast quantification of this class of analytes in minimally pre-treated samples. Herein, we present a novel strategy for engineering a highly efficient surface-enhanced Raman scattering (SERS) spectroscopy platform for the dynamic sensing of biothiols. Colloidally stable silver nanoparticles clusters equipped with a specifically designed azobenzene derivative (AzoProbe) were generated as highly SERS active substrates. In the presence of small biothiols (e.g., glutathione, GSH), breakage of the AzoProbe diazo bond causes drastic spectral changes that can be quantitatively correlated with the biothiol content with a limit of detection of ca. 5 nM for GSH. An identical response was observed for other low molecular weight thiols, while larger macromolecules with free thiol groups (e.g., bovine serum albumin) do not produce distinguishable spectral alterations. This indicates the suitability of the SERS sensing platform for the selective quantification of small biothiols. Full article
(This article belongs to the Topic Advanced Nanomaterials for Sensing Applications)
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12 pages, 2013 KiB  
Article
Face-to-Face Assembly of Ag Nanoplates on Filter Papers for Pesticide Detection by Surface-Enhanced Raman Spectroscopy
by Sulin Jiao, Yixin Liu, Shenli Wang, Shuo Wang, Fengying Ma, Huiyu Yuan, Haibo Zhou, Guangchao Zheng, Yuan Zhang, Kun Dai and Chuntai Liu
Nanomaterials 2022, 12(9), 1398; https://doi.org/10.3390/nano12091398 - 19 Apr 2022
Cited by 15 | Viewed by 2870
Abstract
Surface-enhanced Raman spectroscopy (SERS) technology has been regarded as a most efficient and sensitive strategy for the detection of pollutants at ultra-low concentrations. Fabrication of SERS substrates is of key importance in obtaining the homogeneous and sensitive SERS signals. Cellulose filter papers loaded [...] Read more.
Surface-enhanced Raman spectroscopy (SERS) technology has been regarded as a most efficient and sensitive strategy for the detection of pollutants at ultra-low concentrations. Fabrication of SERS substrates is of key importance in obtaining the homogeneous and sensitive SERS signals. Cellulose filter papers loaded with plasmonic metal NPs are well known as cost-effective and efficient paper-based SERS substrates. In this manuscript, face-to-face assembly of silver nanoplates via solvent-evaporation strategies on the cellulose filter papers has been developed for the SERS substrates. Furthermore, these developed paper-based SERS substrates are utilized for the ultra-sensitive detection of the rhodamine 6G dye and thiram pesticides. Our theoretical studies reveal the creation of high density hotspots, with a huge localized and enhanced electromagnetic field, near the corners of the assembled structures, which justifies the ultrasensitive SERS signal in the fabricated paper-based SERS platform. This work provides an excellent paper-based SERS substrate for practical applications, and one which can also be beneficial to human health and environmental safety. Full article
(This article belongs to the Topic Advanced Nanomaterials for Sensing Applications)
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12 pages, 1586 KiB  
Article
Aptamer-Adjusted Carbon Dot Catalysis-Silver Nanosol SERS Spectrometry for Bisphenol A Detection
by Yuqi Xie, Lu Ma, Shaoming Ling, Huixiang Ouyang, Aihui Liang and Zhiliang Jiang
Nanomaterials 2022, 12(8), 1374; https://doi.org/10.3390/nano12081374 - 17 Apr 2022
Cited by 11 | Viewed by 2827
Abstract
Carbon dots (CDs) can be prepared from various organic (abundant) compounds that are rich in surfaces with –OH, –COOH, and –NH2 groups. Therefore, CDs exhibit good biocompatibility and electron transfer ability, allowing flexible surface modification and accelerated electron transfer during catalysis. Herein, [...] Read more.
Carbon dots (CDs) can be prepared from various organic (abundant) compounds that are rich in surfaces with –OH, –COOH, and –NH2 groups. Therefore, CDs exhibit good biocompatibility and electron transfer ability, allowing flexible surface modification and accelerated electron transfer during catalysis. Herein, CDs were prepared using a hydrothermal method with fructose, saccharose, and citric acid as C sources and urea as an N dopant. The as-prepared CDs were used to catalyze AgNO3–trisodium citrate (TSC) to produce Ag nanoparticles (AgNPs). The surface-enhanced Raman scattering (SERS) intensity increased with the increasing CDs concentration with Victoria blue B (VBB) as a signal molecule. The CDs exhibited a strong catalytic activity, with the highest activity shown by fructose-based CDs. After N doping, catalytic performance improved; with the passivation of a wrapped aptamer, the electron transfer was effectively disrupted (retarded). This resulted in the inhibition of the reaction and a decrease in the SERS intensity. When bisphenol A (BPA) was added, it specifically bound to the aptamer and CDs were released, recovering catalytical activity. The SERS intensity increased with BPA over the concentration range of 0.33–66.67 nmol/L. Thus, the aptamer-adjusted nanocatalytic SERS method can be applied for BPA detection. Full article
(This article belongs to the Topic Advanced Nanomaterials for Sensing Applications)
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14 pages, 4498 KiB  
Article
Study of Optical Information Recording Mechanism Based on Localized Surface Plasmon Resonance with Au Nanoparticles Array Deposited Media and Ridge-Type Nanoaperture
by Sung-Mook Kang
Nanomaterials 2022, 12(8), 1350; https://doi.org/10.3390/nano12081350 - 14 Apr 2022
Cited by 2 | Viewed by 2073
Abstract
To verify the possibility of multiple localized surface plasmon resonance based optical recording mechanism, the present study has demonstrated that an Au nanoparticles array deposited with media combined with a ridge-type nanoaperture can amplify the |E|2 intensity of the incident [...] Read more.
To verify the possibility of multiple localized surface plasmon resonance based optical recording mechanism, the present study has demonstrated that an Au nanoparticles array deposited with media combined with a ridge-type nanoaperture can amplify the |E|2 intensity of the incident optical light transmitted into the media under specific conditions. Using a numerical Finite-Difference Time-Domain method, we found that the optical intensity amplification first occurred in the near-field region while penetrating the ridge-type nanoaperture, then the second optical amplification phenomenon was induced between the metal nanoparticles, and eventually, the excitation effect was transferred to the inside of the media. In a system consisting of a Gold (Au) NPs deposited media and nanoaperture, various parameters to increase the |E|2 intensity in the near-field region were studied. For an Au nanoparticle size (Cube) = 5 nm × 5 nm × 5 nm, an inter-particle space = 10 nm, and a gap (between nanoaperture and media) = 5 nm, the |E|2 intensity of a ridge-type nanoaperture with an Au nanoparticles array was found to be ~47% higher than the |E|2 intensity of a ridge-type nanoaperture without an Au nanoparticles array. Full article
(This article belongs to the Topic Advanced Nanomaterials for Sensing Applications)
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12 pages, 2233 KiB  
Article
Precise and Prompt Analyte Detection via Ordered Orientation of Receptor in WSe2-Based Field Effect Transistor
by Muhammad Shahzad Zafar, Ghulam Dastgeer, Abul Kalam, Abdullah G. Al-Sehemi, Muhammad Imran, Yong Ho Kim and Heeyeop Chae
Nanomaterials 2022, 12(8), 1305; https://doi.org/10.3390/nano12081305 - 11 Apr 2022
Cited by 12 | Viewed by 2922
Abstract
Field-effect transistors (FET) composed of transition metal dichalcogenide (TMDC) materials have gained huge importance as biosensors due to their added advantage of high sensitivity and moderate bandgap. However, the true potential of these biosensors highly depends upon the quality of TMDC material, as [...] Read more.
Field-effect transistors (FET) composed of transition metal dichalcogenide (TMDC) materials have gained huge importance as biosensors due to their added advantage of high sensitivity and moderate bandgap. However, the true potential of these biosensors highly depends upon the quality of TMDC material, as well as the orientation of receptors on their surfaces. The uncontrolled orientation of receptors and screening issues due to crossing the Debye screening length while functionalizing TMDC materials is a big challenge in this field. To address these issues, we introduce a combination of high-quality monolayer WSe2 with our designed Pyrene-based receptor moiety for its ordered orientation onto the WSe2 FET biosensor. A monolayer WSe2 sheet is utilized to fabricate an ideal FET for biosensing applications, which is characterized via Raman spectroscopy, atomic force microscopy, and electrical prob station. Our construct can sensitively detect our target protein (streptavidin) with 1 pM limit of detection within a short span of 2 min, through a one-step functionalizing process. In addition to having this ultra-fast response and high sensitivity, our biosensor can be a reliable platform for point-of-care-based diagnosis. Full article
(This article belongs to the Topic Advanced Nanomaterials for Sensing Applications)
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8 pages, 3686 KiB  
Article
Explaining the Frequency Dependence of the DC-Biased Dielectric Response of Polar Nanoregions by Field-Enhanced Correlation Length
by Jianwei Zhang, Xiaoping Du, Jiguang Zhao and Yongsheng Duan
Nanomaterials 2022, 12(8), 1293; https://doi.org/10.3390/nano12081293 - 11 Apr 2022
Cited by 1 | Viewed by 1673
Abstract
Understanding the effects of polar nanoregions (PNRs) dynamics on dielectric properties is a complex question of essential importance for both fundamental studies of relaxor ferroelectrics and their applications to electro-optic devices. The frequency dependence of dielectric response to the bias electric field opens [...] Read more.
Understanding the effects of polar nanoregions (PNRs) dynamics on dielectric properties is a complex question of essential importance for both fundamental studies of relaxor ferroelectrics and their applications to electro-optic devices. The frequency dependence of dielectric response to the bias electric field opens a brand new window for the study of this problem. A novel model from mesoscopic to macroscopic, revealing the relationship between the dielectric permittivity to the applied electric field, temperature, and PNRs, was established based on mean field approximation and the theory of continuum percolation, and not only validates the field-induced percolation and the relaxation time divergency at the freezing temperature, but also predicts the frequency dependence of dielectric response. Unexpectedly, the model reveals the field-enhanced correlation length results in the nonmonotonic behavior of dielectric response, and implies that the increased orientation consistency of dipolar clusters and coercive fields originated from inherent inhomogeneity slow down the relaxation time of PNR reorientation. Considering the multi-scale heterogeneity of PNRs in relaxor, we found that the increased heterogeneity degree reduces the dielectric permittivity, but changes the slope of dielectric response to the bias electric field. Full article
(This article belongs to the Topic Advanced Nanomaterials for Sensing Applications)
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17 pages, 5668 KiB  
Article
Aptamer-Based Fluorescence Detection and Selective Disinfection of Salmonella Typhimurium by Using Hollow Carbon Nitride Nanosphere
by Xinyi Liu, Jing Xu, Yang Lou, Chengsi Pan, Yin Zhang and Zhouping Wang
Biosensors 2022, 12(4), 228; https://doi.org/10.3390/bios12040228 - 9 Apr 2022
Cited by 5 | Viewed by 2782
Abstract
Hollow carbon nitride nanosphere (HCNS) was synthesized via the hard template method to improve the fluorescence characteristics, drug delivery ability, and photocatalytic activity. Blue fluorescent HCNS was utilized as a quenching agent and an internal reference to combine with Cy5-labelled aptamer (Cy5-Apt), resulting [...] Read more.
Hollow carbon nitride nanosphere (HCNS) was synthesized via the hard template method to improve the fluorescence characteristics, drug delivery ability, and photocatalytic activity. Blue fluorescent HCNS was utilized as a quenching agent and an internal reference to combine with Cy5-labelled aptamer (Cy5-Apt), resulting in an off-on fluorescence aptasensing method for the detection of Salmonella typhimurium (S. typhimurium). Under optimum conditions, this fluorescence assay presented a linear range from 30 to 3 × 104 CFU mL−1 with a detection limit of 13 CFU mL−1. In addition, HCNS was also used as a drug carrier to load chloramphenicol (Cap) molecules. The Cap-loading amount of HCNS could reach 550 μg mg−1 within 24 h, whereas the corresponding Cap-release amount is 302.5 μg mg−1 under acidic and irradiation conditions. The integration of photocatalyst with antibiotic could endow HCNS-Cap with better disinfection performance. The bactericidal efficiency of HCNS-Cap (95.0%) against S. typhimurium within 12 h was better than those of HCNS (85.1%) and Cap (72.9%). In addition, selective disinfection of S. typhimurium was further realized by decorating aptamer. Within 4 h, almost all S. Typhimurium were inactivated by HCNS-Cap-Apt, whereas only 13.3% and 48.2% of Staphylococcus aureus and Escherichia coli cells were killed, respectively. Therefore, HCNS is a promising bio-platform for aptamer-based fluorescence detection and selective disinfection of S. typhimurium. Full article
(This article belongs to the Topic Advanced Nanomaterials for Sensing Applications)
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17 pages, 6464 KiB  
Article
An Integrated Nanocomposite Proximity Sensor: Machine Learning-Based Optimization, Simulation, and Experiment
by Reza Moheimani, Marcial Gonzalez and Hamid Dalir
Nanomaterials 2022, 12(8), 1269; https://doi.org/10.3390/nano12081269 - 8 Apr 2022
Cited by 7 | Viewed by 2441
Abstract
This paper utilizes multi-objective optimization for efficient fabrication of a novel Carbon Nanotube (CNT) based nanocomposite proximity sensor. A previously developed model is utilized to generate a large data set required for optimization which included dimensions of the film sensor, applied excitation frequency, [...] Read more.
This paper utilizes multi-objective optimization for efficient fabrication of a novel Carbon Nanotube (CNT) based nanocomposite proximity sensor. A previously developed model is utilized to generate a large data set required for optimization which included dimensions of the film sensor, applied excitation frequency, medium permittivity, and resistivity of sensor dielectric, to maximize sensor sensitivity and minimize the cost of the material used. To decrease the runtime of the original model, an artificial neural network (ANN) is implemented by generating a one-thousand samples data set to create and train a black-box model. This model is used as the fitness function of a genetic algorithm (GA) model for dual-objective optimization. We also represented the 2D Pareto Frontier of optimum solutions and scatters of distribution. A parametric study is also performed to discern the effects of the various device parameters. The results provide a wide range of geometrical data leading to the maximum sensitivity at the minimum cost of conductive nanoparticles. The innovative contribution of this research is the combination of GA and ANN, which results in a fast and accurate optimization scheme. Full article
(This article belongs to the Topic Advanced Nanomaterials for Sensing Applications)
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10 pages, 3018 KiB  
Article
In Situ Deformation Monitoring of 3D Woven Composite T-Profile Using MXene Nanoparticles
by Prasad Shimpi, Maria Omastova, Andrey Aniskevich and Daiva Zeleniakiene
Materials 2022, 15(8), 2730; https://doi.org/10.3390/ma15082730 - 7 Apr 2022
Cited by 4 | Viewed by 2510
Abstract
The aim of this study was to develop a process-efficient smart three-dimensional (3D) woven composite T-profile by depositing MXene nanoparticles at the junction for sensing damage and deformation at the junction. Such smart composites could find application in the online health monitoring of [...] Read more.
The aim of this study was to develop a process-efficient smart three-dimensional (3D) woven composite T-profile by depositing MXene nanoparticles at the junction for sensing damage and deformation at the junction. Such smart composites could find application in the online health monitoring of complex-shaped parts. The composites were manufactured by infusing epoxy resin in a single-layer fabric T-profile preform, woven in folded form on a dobby shuttle loom using 300 tex glass roving. The chemically etched Ti3C2Tz MXene nanoparticles were dispersed in deionised water and 10 layers were sprayed at the junction of the composite to form a conductive coating. The MXene-coated composite T-profile specimens were subjected to tensile and fatigue loading to study the electromechanical response of the MXene coating to applied displacement. The results showed that the MXene coating was able to sense the sample deformation till ultimate failure of the composite. The MXene coating was also able to effectively sense the tensile–tensile fatigue loading, carried out at 2000 cycles and 4000 cycles for a 50 N–0.5 Hz and a 100 N–1 Hz load–frequency combination, respectively, while being sensitive to the overall deformation of the composite. The smart complex-shaped composites developed in this work were capable of monitoring their health under tensile and fatigue loading in real time. Full article
(This article belongs to the Topic Advanced Nanomaterials for Sensing Applications)
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10 pages, 4543 KiB  
Article
Self-Assembly of Au–Ag Alloy Hollow Nanochains for Enhanced Plasmon-Driven Surface-Enhanced Raman Scattering
by Weiyan Liu, Jianwen Zhang, Juan Hou, Haibibu Aziguli, Qiming Zhang and Hu Jiang
Nanomaterials 2022, 12(8), 1244; https://doi.org/10.3390/nano12081244 - 7 Apr 2022
Cited by 5 | Viewed by 2277
Abstract
In this paper, Au–Ag alloy hollow nanochains (HNCs) were successfully prepared by a template-free self-assembly method achieved by partial substitution of ligands. The obtained Au–Ag alloy HNCs exhibit stronger enhancement as surface-enhanced Raman scattering (SERS) substrates than Au–Ag alloy hollow nanoparticles (HNPs) and [...] Read more.
In this paper, Au–Ag alloy hollow nanochains (HNCs) were successfully prepared by a template-free self-assembly method achieved by partial substitution of ligands. The obtained Au–Ag alloy HNCs exhibit stronger enhancement as surface-enhanced Raman scattering (SERS) substrates than Au–Ag alloy hollow nanoparticles (HNPs) and Au nanochains substrates with an intensity ratio of about 1.3:1:1. Finite difference time domain (FDTD) simulations show that the SERS enhancement of Au–Ag alloy HNCs substrates is produced by a synergistic effect between the plasmon hybridization effect associated with the unique alloy hollow structure and the strong “hot spot” in the interstitial regions of the nanochains. Full article
(This article belongs to the Topic Advanced Nanomaterials for Sensing Applications)
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14 pages, 2672 KiB  
Article
Complex Study of Magnetization Reversal Mechanisms of FeNi/FeMn Bilayers Depending on Growth Conditions
by Christina Gritsenko, Vladimir Lepalovskij, Mikhail Volochaev, Vladimir Komanický, Aleksandr Gorkovenko, Hanna Pazniak, Maria Gazda, Nikolai Andreev and Valeria Rodionova
Nanomaterials 2022, 12(7), 1178; https://doi.org/10.3390/nano12071178 - 1 Apr 2022
Cited by 4 | Viewed by 2277
Abstract
Magnetization reversal processes in the NiFe/FeMn exchange biased structures with various antiferromagnetic layer thicknesses (0–50 nm) and glass substrate temperatures (17–600 °C) during deposition were investigated in detail. Magnetic measurements were performed in the temperature range from 80 K up to 300 K. [...] Read more.
Magnetization reversal processes in the NiFe/FeMn exchange biased structures with various antiferromagnetic layer thicknesses (0–50 nm) and glass substrate temperatures (17–600 °C) during deposition were investigated in detail. Magnetic measurements were performed in the temperature range from 80 K up to 300 K. Hysteresis loop asymmetry was found at temperatures lower than 150 K for the samples with an antiferromagnetic layer thickness of more than 10 nm. The average grain size of FeMn was found to increase with the AFM layer increase, and to decrease with the substrate temperature increase. Hysteresis loop asymmetry was explained in terms of the exchange spring model in the antiferromagnetic layer. Full article
(This article belongs to the Topic Advanced Nanomaterials for Sensing Applications)
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12 pages, 2563 KiB  
Article
Morphology Effect of Bismuth Vanadate on Electrochemical Sensing for the Detection of Paracetamol
by Ying Liu, Xiaocui Xu, Churong Ma, Feng Zhao and Kai Chen
Nanomaterials 2022, 12(7), 1173; https://doi.org/10.3390/nano12071173 - 1 Apr 2022
Cited by 13 | Viewed by 2955
Abstract
Morphology-control, as a promising and effective strategy, is widely implemented to change surface atomic active sites and thus enhance the intrinsic electrocatalytic activity and selectivity. As a typical n-type semiconductor, a series of bismuth vanadate samples with tunable morphologies of clavate, fusiform, flowered, [...] Read more.
Morphology-control, as a promising and effective strategy, is widely implemented to change surface atomic active sites and thus enhance the intrinsic electrocatalytic activity and selectivity. As a typical n-type semiconductor, a series of bismuth vanadate samples with tunable morphologies of clavate, fusiform, flowered, bulky, and nanoparticles were prepared to investigate the morphology effect. Among all the synthesized samples, the clavate shaped BiVO4 with high index facets of (112), (301), and (200) exhibited reduced extrinsic pseudocapacitance and enhanced redox response, which is beneficial for tackling the sluggish voltammetric response of the traditional nanoparticle on the electrode surface. Benefiting from the large surface-active area and favorable ion diffusion channels, the clavate shaped BiVO4 exhibited the best electrochemical sensing performance for paracetamol with a linear response in the range of 0.5–100 µmol and a low detection limit of 0.2 µmol. The enhanced electrochemical detection of paracetamol by bismuth vanadate nanomaterials with controllable shapes indicates their potential for applications as electrochemical sensors. Full article
(This article belongs to the Topic Advanced Nanomaterials for Sensing Applications)
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14 pages, 4158 KiB  
Article
Synergistic Enhancement Properties of a Flexible Integrated PAN/PVDF Piezoelectric Sensor for Human Posture Recognition
by Jiliang Mu, Shuai Xian, Junbin Yu, Juanhong Zhao, Jinsha Song, Zhengyang Li, Xiaojuan Hou, Xiujian Chou and Jian He
Nanomaterials 2022, 12(7), 1155; https://doi.org/10.3390/nano12071155 - 31 Mar 2022
Cited by 25 | Viewed by 3254
Abstract
The flexible pressure sensor has attracted much attention due to its wearable and conformal advantage. All the same, enhancing its electrical and structural properties is still a huge challenge. Herein, a flexible integrated pressure sensor (FIPS) composed of a solid silicone rubber matrix, [...] Read more.
The flexible pressure sensor has attracted much attention due to its wearable and conformal advantage. All the same, enhancing its electrical and structural properties is still a huge challenge. Herein, a flexible integrated pressure sensor (FIPS) composed of a solid silicone rubber matrix, composited with piezoelectric powers of polyacrylonitrile/Polyvinylidene fluoride (PAN/PVDF) and conductive silver-coated glass microspheres is first proposed. Specifically, the mass ratio of the PAN/PVDF and the rubber is up to 4:5 after mechanical mixing. The output voltage of the sensor with composite PAN/PVDF reaches 49 V, which is 2.57 and 3.06 times that with the single components, PAN and PVDF, respectively. In the range from 0 to 800 kPa, its linearity of voltage and current are all close to 0.986. Meanwhile, the sensor retains high voltage and current sensitivities of 42 mV/kPa and 0.174 nA/kPa, respectively. Furthermore, the minimum response time is 43 ms at a frequency range of 1–2.5 Hz in different postures, and the stability is verified over 10,000 cycles. In practical measurements, the designed FIPS showed excellent recognition abilities for various gaits and different bending degrees of fingers. This work provides a novel strategy to improve the flexible pressure sensor, and demonstrates an attractive potential in terms of human health and motion monitoring. Full article
(This article belongs to the Topic Advanced Nanomaterials for Sensing Applications)
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17 pages, 896 KiB  
Article
Convective Heat Transfer Analysis for Aluminum Oxide (Al2O3)- and Ferro (Fe3O4)-Based Nano-Fluid over a Curved Stretching Sheet
by Asifa Ashraf, Zhiyue Zhang, Tareq Saeed, Hussan Zeb and Taj Munir
Nanomaterials 2022, 12(7), 1152; https://doi.org/10.3390/nano12071152 - 30 Mar 2022
Cited by 13 | Viewed by 2181
Abstract
In this work, the combined effects of velocity slip and convective heat boundary conditions on a hybrid nano-fluid over a nonlinear curved stretching surface were considered. Two kinds of fluids, namely, hybrid nano-fluid and aluminum oxide (Al2O3)- [...] Read more.
In this work, the combined effects of velocity slip and convective heat boundary conditions on a hybrid nano-fluid over a nonlinear curved stretching surface were considered. Two kinds of fluids, namely, hybrid nano-fluid and aluminum oxide (Al2O3)- and iron oxide (Fe3O4)-based nano-fluid, were also taken into account. We transformed the governing model into a nonlinear system of ordinary differential equations (ODEs). For this we used the similarity transformation method. The solution of the transformed ODE system was computed via a higher-order numerical approximation scheme known as the shooting method with the Runge–Kutta method of order four (RK-4). It is noticed that the fluid velocity was reduced for the magnetic parameter, curvature parameter, and slip parameters, while the temperature declined with higher values of the magnetic parameter, Prandtl number, and convective heat transfer. Furthermore, the physical quantities of engineering interest, i.e., the behavior of the skin fraction and the Nusselt number, are presented. These behaviors are also illustrated graphically along with the numerical values in a comparison with previous work in numerical tabular form. Full article
(This article belongs to the Topic Advanced Nanomaterials for Sensing Applications)
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13 pages, 5173 KiB  
Article
An Eco-Friendly Synthetic Approach for Copper Nanoclusters and Their Potential in Lead Ions Sensing and Biological Applications
by Sayed M. Saleh, Wael A. El-Sayed, May A. El-Manawaty, Malek Gassoumi and Reham Ali
Biosensors 2022, 12(4), 197; https://doi.org/10.3390/bios12040197 - 26 Mar 2022
Cited by 15 | Viewed by 2709
Abstract
A new preparation route for high-luminescent blue-emission pepsin copper nanoclusters (Pep-CuNCs) is introduced in this work. The synthesized nanoclusters are based on a pepsin molecule, which is a stomach enzyme that works to digest proteins that exist in undigested food. Here, we have [...] Read more.
A new preparation route for high-luminescent blue-emission pepsin copper nanoclusters (Pep-CuNCs) is introduced in this work. The synthesized nanoclusters are based on a pepsin molecule, which is a stomach enzyme that works to digest proteins that exist in undigested food. Here, we have developed an eco-friendly technique through microwave-assisted fast synthesis. The resulting copper nanoclusters (CuNCs) exhibit significant selectivity towards Pb(II) ions. The pepsin molecule was utilized as a stabilizer and reducing agent in the production procedure of Pep-CuNCs. The characteristics of the resulting Pep-CuNCs were studied in terms of size, surface modification, and composition using various sophisticated techniques. The CuNCs responded to Pb(II) ions through the fluorescence quenching mechanism of the CuNCs’ fluorescence. Thus, great selectivity of Pep-CuNCs towards Pb(II) ions was observed, allowing sensitive determination of this metal ion at lab-scale and in the environment. The CuNCs have detection limits for Pb(II) in very tenuous concentration at a nanomalar scale (11.54 nM). The resulting Pep-CuNCs were utilized significantly to detect Pb(II) ions in environmental samples. Additionally, the activity of Pep-CuNCs on different human tumor cell lines was investigated. The data for the observed behavior indicate that the Pep-CuNCs displayed their activity against cancer cells in a dose dependent manner against most utilized cancer cell lines. Full article
(This article belongs to the Topic Advanced Nanomaterials for Sensing Applications)
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14 pages, 3583 KiB  
Article
Quantitative Detection of Mastitis Factor IL-6 in Dairy Cow Using the SERS Improved Immunofiltration Assay
by Ruipeng Chen, Hui Wang, Yiguang Zhao, Xuemei Nan, Wensong Wei, Chunmei Du, Fan Zhang, Qingyao Luo, Liang Yang and Benhai Xiong
Nanomaterials 2022, 12(7), 1091; https://doi.org/10.3390/nano12071091 - 26 Mar 2022
Cited by 7 | Viewed by 2656
Abstract
Interleukin-6 (IL-6) is generally used as a biomarker for the evaluation of inflammatory infection in humans and animals. However, there is no approach for the on-site and rapid detection of IL-6 for the monitoring of mastitis in dairy farm scenarios. A rapid and [...] Read more.
Interleukin-6 (IL-6) is generally used as a biomarker for the evaluation of inflammatory infection in humans and animals. However, there is no approach for the on-site and rapid detection of IL-6 for the monitoring of mastitis in dairy farm scenarios. A rapid and highly sensitive surface enhanced Raman scattering (SERS) immunofiltration assay (IFA) for IL-6 detection was developed in the present study. In this assay, a high sensitivity gold core silver shell SERS nanotag with Raman molecule 4-mercaptobenzoic acid (4-MBA) embedded into the gap was fabricated for labelling. Through the immuno-specific combination of the antigen and antibody, antibody conjugated SERS nanotags were captured on the test zone, which facilitated the SERS measurement. The quantitation of IL-6 was performed by the readout Raman signal in the test region. The results showed that the detection limit (LOD) of IL-6 in milk was 0.35 pg mL−1, which was far below the threshold value of 254.32 pg mL−1. The recovery of the spiking experiment was 87.0–102.7%, with coefficients of variation below 9.0% demonstrating high assay accuracy and precision. We believe the immunosensor developed in the current study could be a promising tool for the rapid assessment of mastitis by detecting milk IL-6 in dairy cows. Moreover, this versatile immunosensor could also be applied for the detection of a wide range of analytes in dairy cow healthy monitoring. Full article
(This article belongs to the Topic Advanced Nanomaterials for Sensing Applications)
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15 pages, 4655 KiB  
Article
Simultaneous Electrochemical Sensing of Indole-3-Acetic Acid and Salicylic Acid on Poly(L-Proline) Nanoparticles–Carbon Dots–Multiwalled Carbon Nanotubes Composite-Modified Electrode
by Mengxue Li, Yiwen Kuang, Ziyan Fan, Xiaoli Qin, Shiyu Hu, Zhanning Liang, Qilin Liu, Weizhong Zhang, Birui Wang and Zhaohong Su
Sensors 2022, 22(6), 2222; https://doi.org/10.3390/s22062222 - 13 Mar 2022
Cited by 12 | Viewed by 4026
Abstract
Sensitive simultaneous electrochemical sensing of phytohormones indole-3-acetic acid and salicylic acid based on a novel poly(L-Proline) nanoparticles–carbon dots composite consisting of multiwalled carbon nanotubes was reported in this study. The poly(L-Proline) nanoparticles–carbon dots composite was facilely prepared by the hydrothermal method, and L-Proline [...] Read more.
Sensitive simultaneous electrochemical sensing of phytohormones indole-3-acetic acid and salicylic acid based on a novel poly(L-Proline) nanoparticles–carbon dots composite consisting of multiwalled carbon nanotubes was reported in this study. The poly(L-Proline) nanoparticles–carbon dots composite was facilely prepared by the hydrothermal method, and L-Proline was used as a monomer and carbon source for the preparation of poly(L-Proline) nanoparticles and carbon dots, respectively. Then, the poly(L-Proline) nanoparticles–carbon dots–multiwalled carbon nanotubes composite was prepared by ultrasonic mixing of poly(L-Proline) nanoparticles–carbon dots composite dispersion and multiwalled carbon nanotubes. Scanning electron microscope, transmission electron microscope, Fourier transform infrared spectroscopy, ultraviolet visible spectroscopy, energy dispersive spectroscopy, cyclic voltammetry, electrochemical impedance spectroscopy, and linear sweep voltammetry were used to characterize the properties of the composite. poly(L-Proline) nanoparticles were found to significantly enhance the conductivity and sensing performance of the composite. Under optimal conditions, the composite-modified electrode exhibited a wide linear range from 0.05 to 25 μM for indole-3-acetic acid and from 0.2 to 60 μM for salicylic acid with detection limits of 0.007 μM and 0.1 μM (S/N = 3), respectively. In addition, the proposed sensor was also applied to simultaneously test indole-3-acetic acid and salicylic acid in real leaf samples with satisfactory recovery. Full article
(This article belongs to the Topic Advanced Nanomaterials for Sensing Applications)
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