Biosensors

11 pages, 1729 KiB

Open AccessArticle

Target-Specific Exosome Isolation through Aptamer-Based Microfluidics

by Zixuan Zhou, Yan Chen and Xiang Qian

Biosensors 2022, 12(4), 257; https://doi.org/10.3390/bios12040257 - 18 Apr 2022

Cited by 18 | Viewed by 4385

Exosomes (30–100 nm in diameter) are a group of cell-derived membrane vesicles, packaged as valuable cargo with lipid, proteins, and genetic materials from their parent cells. With the increasing interest in exosomes for diagnostic and therapeutic applications, the rapid isolation of pure exosome [...] Read more.

Exosomes (30–100 nm in diameter) are a group of cell-derived membrane vesicles, packaged as valuable cargo with lipid, proteins, and genetic materials from their parent cells. With the increasing interest in exosomes for diagnostic and therapeutic applications, the rapid isolation of pure exosome populations has become a hot topic. In this paper, we propose modified microchannels with aptamer in a microfluidics system for rapid and efficient isolation of exosomes by targeting exosome-carrying CD63 and PTK 7. The capture efficiency in surface-modified channels reaches around 10⁷–10⁸ particles/mL in 20 min, and purified exosomes with reliable size can be achieved. Full article

(This article belongs to the Special Issue Microfluidics for Biomedical Applications)

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2 pages, 159 KiB

Open AccessEditorial

Nanomechanical Sensors for Gas Detection towards Artificial Olfaction

by Kosuke Minami

Biosensors 2022, 12(4), 256; https://doi.org/10.3390/bios12040256 - 18 Apr 2022

Cited by 1 | Viewed by 2881

Abstract

Humans, as well as other organisms, tend to recognize their surroundings by smells/odors [...] Full article

(This article belongs to the Special Issue Nanomechanical Sensors for Gas Detection)

12 pages, 3012 KiB

Open AccessArticle

Application of Self-Assembly Nanoparticles Based on DVDMS for Fenton-Like Ion Delivery and Enhanced Sonodynamic Therapy

by Jinqiang Liu, Shiying Fu, Jiaxuan Xie, Jianzhong Zhang, Jintao Pan, Chengchao Chu, Gang Liu and Shenghong Ju

Biosensors 2022, 12(4), 255; https://doi.org/10.3390/bios12040255 - 18 Apr 2022

Cited by 8 | Viewed by 4345

Abstract

Upon harnessing low-intensity ultrasound to activate sonosensitizers, sonodynamic therapy (SDT) induces cancer cell death through the reactive oxygen species (ROS) mediated pathway. Compared with photodynamic therapy (PDT), SDT possesses numerous advantages, including deeper tissue penetration, higher accuracy, fewer side effects, and better patient [...] Read more.

Upon harnessing low-intensity ultrasound to activate sonosensitizers, sonodynamic therapy (SDT) induces cancer cell death through the reactive oxygen species (ROS) mediated pathway. Compared with photodynamic therapy (PDT), SDT possesses numerous advantages, including deeper tissue penetration, higher accuracy, fewer side effects, and better patient compliance. Sinoporphyrin sodium (DVDMS), a sonosensitizer approved by the FDA, has drawn abundant attention in clinical research, but there are some deficiencies. In order to further improve the efficiency of DVDMS, many studies have applied self-assembly nanotechnology to modify it. Furthermore, the combined applications of SDT/chemodynamic therapy (CDT) have become a research hotspot in tumor therapy. Therefore, we explored the self-assembly of nanoparticles based on DVDMS and copper to combine SDT and CDT. A cost-effective sonosensitizer was synthesized by dropping CuCl₂ into the DVDMS solution with the assistance of PVP. The results revealed that the nanostructures could exert excellent treatment effects on tumor therapy and perform well for PET imaging, indicating the potential for cancer theranostics. In vitro and in vivo experiments showed that the nanoparticles have outstanding biocompatibility, higher ROS production efficiency, and antitumor efficacy. We believe this design can represent a simple approach to combining SDT and CDT with potential applications in clinical treatment and PET imaging. Full article

(This article belongs to the Section Biosensors and Healthcare)

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21 pages, 3362 KiB

Open AccessReview

Two-Dimensional Quantum Dot-Based Electrochemical Biosensors

by Jian Zhang, Xiaoyue Zhang and Sai Bi

Biosensors 2022, 12(4), 254; https://doi.org/10.3390/bios12040254 - 17 Apr 2022

Cited by 16 | Viewed by 4238

Abstract

Two-dimensional quantum dots (2D-QDs) derived from two-dimensional sheets have received increasing interest owing to their unique properties, such as large specific surface areas, abundant active sites, good aqueous dispersibility, excellent electrical property, easy functionalization, and so on. A variety of 2D-QDs have been [...] Read more.

Two-dimensional quantum dots (2D-QDs) derived from two-dimensional sheets have received increasing interest owing to their unique properties, such as large specific surface areas, abundant active sites, good aqueous dispersibility, excellent electrical property, easy functionalization, and so on. A variety of 2D-QDs have been developed based on different materials including graphene, black phosphorus, nitrides, transition metal dichalcogenides, transition metal oxides, and MXenes. These 2D-QDs share some common features due to the quantum confinement effects and they also possess unique properties owing to their structural differences. In this review, we discuss the categories, properties, and synthetic routes of these 2D-QDs and emphasize their applications in electrochemical biosensors. We deeply hope that this review not only stimulates more interest in 2D-QDs, but also promotes further development and applications of 2D-QDs in various research fields. Full article

(This article belongs to the Special Issue Advances in Quantum Dots Biosensing)

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27 pages, 3654 KiB

Open AccessReview

Nanomaterial-Based Label-Free Electrochemical Aptasensors for the Detection of Thrombin

by Hibba Yousef, Yang Liu and Lianxi Zheng

Biosensors 2022, 12(4), 253; https://doi.org/10.3390/bios12040253 - 16 Apr 2022

Cited by 19 | Viewed by 4470

Abstract

Thrombin plays a central role in hemostasis and its imbalances in coagulation can lead to various pathologies. It is of clinical significance to develop a fast and accurate method for the quantitative detection of thrombin. Electrochemical aptasensors have the capability of combining the [...] Read more.

Thrombin plays a central role in hemostasis and its imbalances in coagulation can lead to various pathologies. It is of clinical significance to develop a fast and accurate method for the quantitative detection of thrombin. Electrochemical aptasensors have the capability of combining the specific selectivity from aptamers with the extraordinary sensitivity from electrochemical techniques and thus have attracted considerable attention for the trace-level detection of thrombin. Nanomaterials and nanostructures can further enhance the performance of thrombin aptasensors to achieve high sensitivity, selectivity, and antifouling functions. In highlighting these material merits and their impacts on sensor performance, this paper reviews the most recent advances in label-free electrochemical aptasensors for thrombin detection, with an emphasis on nanomaterials and nanostructures utilized in sensor design and fabrication. The performance, advantages, and limitations of those aptasensors are summarized and compared according to their material structures and compositions. Full article

(This article belongs to the Special Issue Biosensors in Nanotechnology)

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30 pages, 3365 KiB

Open AccessReview

A Review on Flexible Electrochemical Biosensors to Monitor Alcohol in Sweat

by Nuna G. Costa, Joana C. Antunes, Antonio J. Paleo and Ana M. Rocha

Biosensors 2022, 12(4), 252; https://doi.org/10.3390/bios12040252 - 16 Apr 2022

Cited by 14 | Viewed by 5807

Abstract

The continued focus on improving the quality of human life has encouraged the development of increasingly efficient, durable, and cost-effective products in healthcare. Over the last decade, there has been substantial development in the field of technical and interactive textiles that combine expertise [...] Read more.

The continued focus on improving the quality of human life has encouraged the development of increasingly efficient, durable, and cost-effective products in healthcare. Over the last decade, there has been substantial development in the field of technical and interactive textiles that combine expertise in electronics, biology, chemistry, and physics. Most recently, the creation of textile biosensors capable of quantifying biometric data in biological fluids is being studied, to detect a specific disease or the physical condition of an individual. The ultimate goal is to provide access to medical diagnosis anytime and anywhere. Presently, alcohol is considered the most commonly used addictive substance worldwide, being one of the main causes of death in road accidents. Thus, it is important to think of solutions capable of minimizing this public health problem. Alcohol biosensors constitute an excellent tool to aid at improving road safety. Hence, this review explores concepts about alcohol biomarkers, the composition of human sweat and the correlation between alcohol and blood. Different components and requirements of a biosensor are reviewed, along with the electrochemical techniques to evaluate its performance, in addition to construction techniques of textile-based biosensors. Special attention is given to the determination of biomarkers that must be low cost and fast, so the use of biomimetic materials to recognize and detect the target analyte is turning into an attractive option to improve electrochemical behavior. Full article

(This article belongs to the Section Biosensor and Bioelectronic Devices)

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21 pages, 4869 KiB

Open AccessReview

Nanozymes with Multiple Activities: Prospects in Analytical Sensing

by Xiangheng Niu, Bangxiang Liu, Panwang Hu, Hengjia Zhu and Mengzhu Wang

Biosensors 2022, 12(4), 251; https://doi.org/10.3390/bios12040251 - 16 Apr 2022

Cited by 35 | Viewed by 5204

Abstract

Given the superiorities in catalytic stability, production cost and performance tunability over natural bio-enzymes, artificial nanomaterials featuring enzyme-like characteristics (nanozymes) have drawn extensive attention from the academic community in the past decade. With these merits, they are intensively tested for sensing, biomedicine and [...] Read more.

Given the superiorities in catalytic stability, production cost and performance tunability over natural bio-enzymes, artificial nanomaterials featuring enzyme-like characteristics (nanozymes) have drawn extensive attention from the academic community in the past decade. With these merits, they are intensively tested for sensing, biomedicine and environmental engineering. Especially in the analytical sensing field, enzyme mimics have found wide use for biochemical detection, environmental monitoring and food analysis. More fascinatingly, rational design enables one fabrication of enzyme-like materials with versatile activities, which show great promise for further advancement of the nanozyme-involved biochemical sensing field. To understand the progress in such an exciting field, here we offer a review of nanozymes with multiple catalytic activities and their analytical application prospects. The main types of enzyme-mimetic activities are first introduced, followed by a summary of current strategies that can be employed to design multi-activity nanozymes. In particular, typical materials with at least two enzyme-like activities are reviewed. Finally, opportunities for multi-activity nanozymes applied in the sensing field are discussed, and potential challenges are also presented, to better guide the development of analytical methods and sensors using nanozymes with different catalytic features. Full article

(This article belongs to the Special Issue Biosensors in Food Analysis and Environmental Detection)

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16 pages, 2229 KiB

Open AccessArticle

Label-Free Differentiation of Cancer and Non-Cancer Cells Based on Machine-Learning-Algorithm-Assisted Fast Raman Imaging

by Qing He, Wen Yang, Weiquan Luo, Stefan Wilhelm and Binbin Weng

Biosensors 2022, 12(4), 250; https://doi.org/10.3390/bios12040250 - 15 Apr 2022

Cited by 11 | Viewed by 3854

Abstract

This paper proposes a rapid, label-free, and non-invasive approach for identifying murine cancer cells (B16F10 melanoma cancer cells) from non-cancer cells (C2C12 muscle cells) using machine-learning-assisted Raman spectroscopic imaging. Through quick Raman spectroscopic imaging, a hyperspectral data processing approach based on machine learning [...] Read more.

This paper proposes a rapid, label-free, and non-invasive approach for identifying murine cancer cells (B16F10 melanoma cancer cells) from non-cancer cells (C2C12 muscle cells) using machine-learning-assisted Raman spectroscopic imaging. Through quick Raman spectroscopic imaging, a hyperspectral data processing approach based on machine learning methods proved capable of presenting the cell structure and distinguishing cancer cells from non-cancer muscle cells without compromising full-spectrum information. This study discovered that biomolecular information–nucleic acids, proteins, and lipids—from cells could be retrieved efficiently from low-quality hyperspectral Raman datasets and then employed for cell line differentiation. Full article

(This article belongs to the Special Issue Nanosensors for the Detection and Characterization of Food, Environmental and Medical Samples)

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10 pages, 1455 KiB

Open AccessArticle

A Simple and Universal Nucleic Acid Assay Platform Based on Personal Glucose Meter Using SARS-CoV-2 N Gene as the Model

by Tian Li, Rui Pan, Yuhan Wen, Jiaqi Xu, Liping Zhang, Suna He and Gaofeng Liang

Biosensors 2022, 12(4), 249; https://doi.org/10.3390/bios12040249 - 15 Apr 2022

Cited by 5 | Viewed by 2413

Abstract

A simple, selective, and quantitative platform for point-of-care diagnostic of COVID-19 is urgently needed as a complement in areas where resources are currently relatively scarce. To meet the needs of early diagnosis and intervention, a proof-of-concept demonstration of a universal personal glucose meter-based [...] Read more.

A simple, selective, and quantitative platform for point-of-care diagnostic of COVID-19 is urgently needed as a complement in areas where resources are currently relatively scarce. To meet the needs of early diagnosis and intervention, a proof-of-concept demonstration of a universal personal glucose meter-based nucleic acid assay platform (PGM-NAAP) is presented, which converts to SARS-CoV-2 detection from glucose detection. By using magnetic bead separation together with the hand-held PGM for quantitative readout, PGM-NAAP achieves the 98 pM limit of detection for a sequence related to SARS-CoV-2. The ability to discriminate target nucleic acid from genomic DNA, the satisfactory spike recoveries of saliva and serum samples, as well as the good stability all together suggest the potential of the PGM-NAAP for the screening and diagnosis of suspected patients during the outbreaks of COVID-19 in resource-limited settings without sophisticated instruments. On the basis of these findings, PGM-NAAP can be expected to provide an accurate and convenient path for diagnosis of disease-associated nucleic acid. Full article

(This article belongs to the Special Issue Fast and Sensitive Detection of Nucleic Acid)

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11 pages, 4250 KiB

Open AccessCommunication

Colorimetric Sensing of Lactate in Human Sweat Using Polyaniline Nanoparticles-Based Sensor Platform and Colorimeter

by Hyun Jung Kim, Insu Park, Seung Pil Pack, Gyudo Lee and Yoochan Hong

Biosensors 2022, 12(4), 248; https://doi.org/10.3390/bios12040248 - 15 Apr 2022

Cited by 17 | Viewed by 3746

Abstract

In emergency medicine, the lactate level is commonly used as an indicator of the severity and response to the treatment of hypoperfusion-related diseases. Clinical lactate measurements generally require 3 h for clinical determination. To improve the current gold standard methods, the development of [...] Read more.

In emergency medicine, the lactate level is commonly used as an indicator of the severity and response to the treatment of hypoperfusion-related diseases. Clinical lactate measurements generally require 3 h for clinical determination. To improve the current gold standard methods, the development of sensor devices that can reduce detection time while maintaining sensitivity and providing portability is gaining great attention. This study aimed to develop a polyaniline (PAni)-based single-sensor platform for sensing lactate in human sweat using a CIELAB color system-based colorimetric device. To establish a lactate sensing platform, PAni nanoparticles were synthesized and adsorbed on the filter paper surface using solvent shift and dip-coating methods, respectively. PAni is characterized by a chemical change accompanied by a color change according to the surrounding environment. To quantify the color change of PAni, a CIELAB color system-based colorimetric device was fabricated. The color change of PAni was measured according to the chemical state using a combination of a PAni-based filter paper sensor platform and a colorimetric device, based on the lactate concentration in deionized water. Finally, human sweat was spiked with lactate to measure the color change of the PAni-based filter paper sensor platform. Under these conditions, the combination of polyaniline-based sensor platforms and colorimetric systems has a limit of detection (LOD) and limit of quantitation (LOQ) of 1 mM, linearity of 0.9684, and stability of 14%. Tbe confirmed that the color of the substrate changes after about 30 s, and through this, the physical fatigue of the individual can be determined. In conclusion, it was confirmed through this study that a combination of the PAni paper sensor platform and colorimeter can detect clinically meaningful lactate concentration. Full article

(This article belongs to the Special Issue Biosensors for Body Fluid Analysis II)

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12 pages, 3145 KiB

Open AccessArticle

An iEEG Recording and Adjustable Shunt-Current Conduction Platform for Epilepsy Treatment

by Changhua You, Lei Yao, Pan Yao, Li Li, Ping Ding, Shuli Liang, Chunxiu Liu and Ning Xue

Biosensors 2022, 12(4), 247; https://doi.org/10.3390/bios12040247 - 15 Apr 2022

Cited by 3 | Viewed by 2871

Abstract

This paper proposes a compact bioelectronics sensing platform, including a multi-channel electrode, intracranial electroencephalogram (iEEG) recorder, adjustable galvanometer, and shunt-current conduction circuit pathway. The developed implantable electrode made of polyurethane-insulated stainless-steel materials is capable of recording iEEG signals and shunt-current conduction. The electrochemical [...] Read more.

This paper proposes a compact bioelectronics sensing platform, including a multi-channel electrode, intracranial electroencephalogram (iEEG) recorder, adjustable galvanometer, and shunt-current conduction circuit pathway. The developed implantable electrode made of polyurethane-insulated stainless-steel materials is capable of recording iEEG signals and shunt-current conduction. The electrochemical impedance of the conduction, ground/reference, and working electrode were characterized in phosphate buffer saline solution, revealing in vitro results of 517.2 Ω@1 kHz (length of 0.1 mm, diameter of 0.8 mm), 1.374 kΩ@1 kHz (length of 0.3 mm, diameter of 0.1 mm), and 3.188 kΩ@1 kHz (length of 0.1 mm, diameter of 0.1 mm), respectively. On-bench measurement of the system revealed that the input noise of the system is less than 2 μVrms, the signal frequency bandwidth range is 1 Hz~10 kHz, and the shunt-current detection range is 0.1~3000 μA with an accuracy of above 99.985%. The electrode was implanted in the CA1 region of the right hippocampus of rats for the in vivo experiments. Kainic acid (KA)-induced seizures were detected through iEEG monitoring, and the induced shunt-current was successfully measured and conducted out of the brain through the designed circuit-body path, which verifies the potential of current conduction for the treatment of epilepsy. Full article

(This article belongs to the Section Biosensor and Bioelectronic Devices)

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17 pages, 5524 KiB

Open AccessArticle

Preparation of Graphene Quantum Dots by Visible-Fenton Reaction and Ultrasensitive Label-Free Immunosensor for Detecting Lipovitellin of Paralichthys Olivaceus

by Ailing Yang, Yue Su, Zhenzhong Zhang, Huaidong Wang, Chong Qi, Shaoguo Ru and Jun Wang

Biosensors 2022, 12(4), 246; https://doi.org/10.3390/bios12040246 - 15 Apr 2022

Cited by 8 | Viewed by 2467

Abstract

The increasing levels of environmental estrogens are causing negative effects on water, soil, wildlife, and human beings; label-free immunosensors with high specificities and sensitivities are being developed to test estrogeneous chemicals in complex environmental conditions. For the first time, highly fluorescent graphene quantum [...] Read more.

The increasing levels of environmental estrogens are causing negative effects on water, soil, wildlife, and human beings; label-free immunosensors with high specificities and sensitivities are being developed to test estrogeneous chemicals in complex environmental conditions. For the first time, highly fluorescent graphene quantum dots (GQDs) were prepared using a visible-Fenton catalysis reaction with graphene oxide (GO) as a precursor. Different microscopy and spectroscopy techniques were employed to characterize the physical and chemical properties of the GQDs. Based on the fluorescence resonance energy transfer (FRET) between amino-functionalized GQDs conjugated with anti-lipovitellin monoclonal antibodies (Anti-Lv-mAb) and reduced graphene oxide (rGO), an ultrasensitive fluorescent “ON-OFF” label-free immunosensor for the detection of lipovitellin (Lv), a sensitive biomarker derived from Paralichthys olivaceus for environmental estrogen, has been established. The immunosensor has a wide linear test range (0.001–1500 ng/mL), a lower limit of detection (LOD, 0.9 pg/mL), excellent sensitivity (26,407.8 CPS/(ng/mL)), and high selectivity and reproducibility for Lv quantification. The results demonstrated that the visible-Fenton is a simple, mild, green, efficient, and general approach to fabricating GQDs, and the fluorescent “ON-OFF” immunosensor is an easy-to-use, time-saving, ultrasensitive, and accurate detection method for weak estrogenic activity. Full article

(This article belongs to the Section Optical and Photonic Biosensors)

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23 pages, 7105 KiB

Open AccessArticle

Optimization Strategies Used for Boosting Piezoelectric Response of Biosensor Based on Flexible Micro-ZnO Composites

by Xiaoting Zhang, Jose Villafuerte, Vincent Consonni, Eirini Sarigiannidou, Jean-Fabien Capsal, Alexis Bruhat, Daniel Grinberg, Lionel Petit, Pierre-Jean Cottinet and Minh-Quyen Le

Biosensors 2022, 12(4), 245; https://doi.org/10.3390/bios12040245 - 14 Apr 2022

Cited by 7 | Viewed by 3015

Abstract

Piezoelectric ZnO-based composites have been explored as a flexible and compact sensor for the implantable biomedical systems used in cardio surgery. In this work, a progressive development route was investigated to enhance the performance of piezoelectric composites incorporated with different shape, concentration and [...] Read more.

Piezoelectric ZnO-based composites have been explored as a flexible and compact sensor for the implantable biomedical systems used in cardio surgery. In this work, a progressive development route was investigated to enhance the performance of piezoelectric composites incorporated with different shape, concentration and connectivity of ZnO fillers. ZnO microrods (MRs) have been successfully synthesized homogeneously in aqueous solution using a novel process-based on chemical bath deposition (CBD) method. The morphological analysis along with Raman scattering and cathodoluminescence spectroscopy of ZnO MRs confirm their high crystalline quality, their orientation along the polar c-axis and the presence of hydrogen-related defects acting as shallow donors in their center. The experimental characterizations highlight that ZnO MR-based composites, with a higher aspect ratio (AR), lead to a significant improvement in the mechanical, dielectric and piezoelectric properties as opposed to the ZnO microparticles (MP) counterparts. The dielectrophoretic (DEP) process is then subjected to both ZnO MP- and MR-based composites, whose performance is expected to be improved as compared to the randomly dispersed composites, thanks to the creation of chain-like structures along the electric field direction. Furthermore, a numerical simulation using COMSOL software is developed to evaluate the influence of the material structuration as well as the filler’s shape on the electric field distribution within different phases (filler, matrix and interface) of the composites. Finally, the aligned MR piezoelectric composites are revealed to be high potential in the development of innovative compact and biocompatible force-sensing devices. Such a technological breakthrough allows the achievement of a real-time precise characterization of mitral valve (MV) coaptation to assist surgeons during MV repair surgery. Full article

(This article belongs to the Special Issue Flexible Biosensors for Health Monitoring)

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Graphical abstract

36 pages, 1355 KiB

Open AccessReview

Graphene-Based Biosensors for Molecular Chronic Inflammatory Disease Biomarker Detection

by Isidro Badillo-Ramírez, Yojana J. P. Carreón, Claudia Rodríguez-Almazán, Claudia M. Medina-Durán, Selene R. Islas and José M. Saniger

Biosensors 2022, 12(4), 244; https://doi.org/10.3390/bios12040244 - 14 Apr 2022

Cited by 15 | Viewed by 4766

Abstract

Chronic inflammatory diseases, such as cancer, diabetes mellitus, stroke, ischemic heart diseases, neurodegenerative conditions, and COVID-19 have had a high number of deaths worldwide in recent years. The accurate detection of the biomarkers for chronic inflammatory diseases can significantly improve diagnosis, as well [...] Read more.

Chronic inflammatory diseases, such as cancer, diabetes mellitus, stroke, ischemic heart diseases, neurodegenerative conditions, and COVID-19 have had a high number of deaths worldwide in recent years. The accurate detection of the biomarkers for chronic inflammatory diseases can significantly improve diagnosis, as well as therapy and clinical care in patients. Graphene derivative materials (GDMs), such as pristine graphene (G), graphene oxide (GO), and reduced graphene oxide (rGO), have shown tremendous benefits for biosensing and in the development of novel biosensor devices. GDMs exhibit excellent chemical, electrical and mechanical properties, good biocompatibility, and the facility of surface modification for biomolecular recognition, opening new opportunities for simple, accurate, and sensitive detection of biomarkers. This review shows the recent advances, properties, and potentialities of GDMs for developing robust biosensors. We show the main electrochemical and optical-sensing methods based on GDMs, as well as their design and manufacture in order to integrate them into robust, wearable, remote, and smart biosensors devices. We also describe the current application of such methods and technologies for the biosensing of chronic disease biomarkers. We also describe the current application of such methods and technologies for the biosensing of chronic disease biomarkers with improved sensitivity, reaching limits of detection from the nano to atto range concentration. Full article

(This article belongs to the Special Issue Biosensors for Multiplex Detection of Biomarkers of Inflammatory Disease)

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11 pages, 2342 KiB

Open AccessArticle

Fiber-Enhanced Stimulated Raman Scattering and Sensitive Detection of Dilute Solutions

by Li Guo, Jing Huang, Yaxin Chen, Bohan Zhang and Minbiao Ji

Biosensors 2022, 12(4), 243; https://doi.org/10.3390/bios12040243 - 14 Apr 2022

Cited by 2 | Viewed by 3335

Abstract

Stimulated Raman scattering (SRS) is known to gain coherent amplification of molecular vibrations that allow for rapid and label-free chemical imaging in the microscopy setting. However, the tightly focused laser spot has limited the detection sensitivity, partly due to the tiny interaction volume. [...] Read more.

Stimulated Raman scattering (SRS) is known to gain coherent amplification of molecular vibrations that allow for rapid and label-free chemical imaging in the microscopy setting. However, the tightly focused laser spot has limited the detection sensitivity, partly due to the tiny interaction volume. Here, we report the use of metal-lined hollow-core fiber (MLHCF) to improve the sensitivity of SRS in sensing dilute solutions by extending the light–matter interaction volume through the fiber waveguide. With a focusing lens (100 mm FL) and 320 μm diameter fiber, we demonstrated an optimum enhancement factor of ~20 at a fiber length of 8.3 cm. More importantly, the MLHCF exhibited a significantly suppressed cross-phase modulation (XPM) background, enabling the detection of ~0.7 mM DMSO in water. Furthermore, the relationship between fiber length and SRS signal could be well explained theoretically. The fiber-enhanced SRS (FE-SRS) method may be further optimized and bears potential in the sensitive detection of molecules in the solution and gas phases. Full article

(This article belongs to the Special Issue Optical Sensors for Bio-Sensing, Imaging and Theranostics Applications)

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11 pages, 1827 KiB

Open AccessArticle

Based on Unmodified Aptamer-Gold Nanoparticles Colorimetric Detection of Dexamethasone in Food

by Yadi Qin, Hayilati Bubiajiaer, Jun Yao and Minwei Zhang

Biosensors 2022, 12(4), 242; https://doi.org/10.3390/bios12040242 - 14 Apr 2022

Cited by 12 | Viewed by 3698

Abstract

Residue and illegal addition of Dexamethasone (DEX) in food has received widespread attention over the past few decades. Long-term intake of DEX will have a strong endocrine-disrupting effect, and there is an urgent need to develop highly sensitive and rapid on-site detection methods. [...] Read more.

Residue and illegal addition of Dexamethasone (DEX) in food has received widespread attention over the past few decades. Long-term intake of DEX will have a strong endocrine-disrupting effect, and there is an urgent need to develop highly sensitive and rapid on-site detection methods. In this work, a colorimetric sensor based on an unmodified aptamer and gold nanoparticles (Au NPs) was designed to detect DEX in milk and glucosamine. Under optimized conditions, the absorbance ratio of Au NPs increased linearly with DEX concentration over the range of 10–350 nmol/mL (r² = 0.997), with a limit of detection (LOD) of 0.5 nmol/mL, and the recoveries ranged from 93.6 to 117%. To explore the interaction mechanism between aptamer and DEX, molecular docking and molecular dynamics simulations were applied to probe intermolecular interactions and structures of the complex. The establishment of aptamer-based sensors effectively avoids the antibody screening response, with a cost-efficient, excellent selective and great potential in DEX determination. Full article

(This article belongs to the Special Issue Nanomaterial-Based Biosensors for Food Analysis)

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21 pages, 4892 KiB

Open AccessArticle

Novel Screen-Printed Sensor with Chemically Deposited Boron-Doped Diamond Electrode: Preparation, Characterization, and Application

by Oleksandr Matvieiev, Renáta Šelešovská, Marian Vojs, Marián Marton, Pavol Michniak, Vojtěch Hrdlička, Michal Hatala, Lenka Janíková, Jaromíra Chýlková, Jana Skopalová, Petr Cankař and Tomáš Navrátil

Biosensors 2022, 12(4), 241; https://doi.org/10.3390/bios12040241 - 13 Apr 2022

Cited by 13 | Viewed by 3899

Abstract

New screen-printed sensor with a boron-doped diamond working electrode (SP/BDDE) was fabricated using a large-area linear antenna microwave chemical deposition vapor system (LA-MWCVD) with a novel precursor composition. It combines the advantages of disposable printed sensors, such as tailored design, low cost, and [...] Read more.

New screen-printed sensor with a boron-doped diamond working electrode (SP/BDDE) was fabricated using a large-area linear antenna microwave chemical deposition vapor system (LA-MWCVD) with a novel precursor composition. It combines the advantages of disposable printed sensors, such as tailored design, low cost, and easy mass production, with excellent electrochemical properties of BDDE, including a wide available potential window, low background currents, chemical resistance, and resistance to passivation. The newly prepared SP/BDDEs were characterized by scanning electron microscopy (SEM) and Raman spectroscopy. Their electrochemical properties were investigated by cyclic voltammetry and electrochemical impedance spectroscopy using inner sphere ([Fe(CN)₆]^4−/3−) and outer sphere ([Ru(NH₃)₆]^2+/3+) redox probes. Moreover, the applicability of these new sensors was verified by analysis of the anti-inflammatory drug lornoxicam in model and pharmaceutical samples. Using optimized differential pulse voltammetry in Britton–Robinson buffer of pH 3, detection limits for lornoxicam were 9 × 10⁻⁸ mol L⁻¹. The oxidation mechanism of lornoxicam was investigated using bulk electrolysis and online electrochemical cell with mass spectrometry; nine distinct reaction steps and corresponding products and intermediates were identified. Full article

(This article belongs to the Topic Frontiers in Fabrication of Screen-Printed Electrodes and Their Applications)

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10 pages, 11864 KiB

Open AccessArticle

Rapid Detection of Deoxynivalenol in Dry Pasta Using a Label-Free Immunosensor

by Francesca Malvano, Roberto Pilloton, Alfredo Rubino and Donatella Albanese

Biosensors 2022, 12(4), 240; https://doi.org/10.3390/bios12040240 - 13 Apr 2022

Cited by 8 | Viewed by 2272

Abstract

This work focused on the development and optimization of an impedimetric label-free immunosensor for detecting deoxynivalenol (DON). A monoclonal antibody for DON detection was immobilized on a modified gold electrode with a cysteamine layer and polyamidoamine (PAMAM) dendrimers. Cyclic voltammetry and electrochemical impedance [...] Read more.

This work focused on the development and optimization of an impedimetric label-free immunosensor for detecting deoxynivalenol (DON). A monoclonal antibody for DON detection was immobilized on a modified gold electrode with a cysteamine layer and polyamidoamine (PAMAM) dendrimers. Cyclic voltammetry and electrochemical impedance spectroscopy techniques were used to monitor the layer-by-layer development of the immunosensor design, while electrochemical impedance spectroscopy and differential pulse voltammetry were employed to investigate the antigen/antibody interaction. The PAMAM dendrimers, allowing to immobilize a large number of monoclonal antibodies, permitted reaching, through the DPV technique, a high sensitivity and a low limit of detection equal to 1 ppb. The evaluation of the possible reuse of the immunosensors highlighted a decrease in the analytical performances of the regenerated immunosensors. After evaluating the matrix effect, the developed immunosensor was used to quantify DON in pasta samples spiked with a known mycotoxin concentration. Taking into consideration the DON extraction procedure used for the pasta samples and the matrix effect related to the sample, the proposed immunosensor showed a limit of detection of 50 ppb, which is lower than the maximum residual limit imposed by European Regulation for DON in dry pasta (750 ppb). Full article

(This article belongs to the Special Issue Optical and Electrical Nanostructured Sensors for Biochemical, Food and Environmental Applications)

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17 pages, 1108 KiB

Open AccessReview

Emerging Methods of Monitoring Volatile Organic Compounds for Detection of Plant Pests and Disease

by Samantha MacDougall, Fatih Bayansal and Ali Ahmadi

Biosensors 2022, 12(4), 239; https://doi.org/10.3390/bios12040239 - 13 Apr 2022

Cited by 27 | Viewed by 7115

Abstract

Each year, unwanted plant pests and diseases, such as Hendel or potato soft rot, cause damage to crops and ecosystems all over the world. To continue to feed the growing population and protect the global ecosystems, the surveillance and management of the spread [...] Read more.

Each year, unwanted plant pests and diseases, such as Hendel or potato soft rot, cause damage to crops and ecosystems all over the world. To continue to feed the growing population and protect the global ecosystems, the surveillance and management of the spread of these pests and diseases are crucial. Traditional methods of detection are often expensive, bulky and require expertise and training. Therefore, inexpensive, portable, and user-friendly methods are required. These include the use of different gas-sensing technologies to exploit volatile organic compounds released by plants under stress. These methods often meet these requirements, although they come with their own set of advantages and disadvantages, including the sheer number of variables that affect the profile of volatile organic compounds released, such as sensitivity to environmental factors and availability of soil nutrients or water, and sensor drift. Furthermore, most of these methods lack research on their use under field conditions. More research is needed to overcome these disadvantages and further understand the feasibility of the use of these methods under field conditions. This paper focuses on applications of different gas-sensing technologies from over the past decade to detect plant pests and diseases more efficiently. Full article

(This article belongs to the Section Environmental Biosensors and Biosensing)

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3 pages, 162 KiB

Open AccessEditorial

Photonic Biosensors: Detection, Analysis and Medical Diagnostics

by Donato Conteduca

Biosensors 2022, 12(4), 238; https://doi.org/10.3390/bios12040238 - 13 Apr 2022

Cited by 1 | Viewed by 2192

Abstract

The necessity of personalised diagnoses and ad hoc treatments for individual patients is driving the outbreak of personalised nanomedicine in research and in clinical studies in the healthcare field [...] Full article

(This article belongs to the Special Issue Photonic Biosensors: Detection, Analysis and Medical Diagnostics)

13 pages, 1963 KiB

Open AccessArticle

Microfluidic One-Pot Digital Droplet FISH Using LNA/DNA Molecular Beacons for Bacteria Detection and Absolute Quantification

by Yu-Ting Kao, Silvia Calabrese, Nadine Borst, Michael Lehnert, Yu-Kai Lai, Franziska Schlenker, Peter Juelg, Roland Zengerle, Piotr Garstecki and Felix von Stetten

Biosensors 2022, 12(4), 237; https://doi.org/10.3390/bios12040237 - 12 Apr 2022

Cited by 4 | Viewed by 4425

Abstract

We demonstrate detection and quantification of bacterial load with a novel microfluidic one-pot wash-free fluorescence in situ hybridization (FISH) assay in droplets. The method offers minimal manual workload by only requiring mixing of the sample with reagents and loading it into a microfluidic [...] Read more.

We demonstrate detection and quantification of bacterial load with a novel microfluidic one-pot wash-free fluorescence in situ hybridization (FISH) assay in droplets. The method offers minimal manual workload by only requiring mixing of the sample with reagents and loading it into a microfluidic cartridge. By centrifugal microfluidic step emulsification, our method partitioned the sample into 210 pL (73 µm in diameter) droplets for bacterial encapsulation followed by in situ permeabilization, hybridization, and signal detection. Employing locked nucleic acid (LNA)/DNA molecular beacons (LNA/DNA MBs) and NaCl-urea based hybridization buffer, the assay was characterized with Escherichia coli, Klebsiella pneumonia, and Proteus mirabilis. The assay performed with single-cell sensitivity, a 4-log dynamic range from a lower limit of quantification (LLOQ) at ~3 × 10³ bacteria/mL to an upper limit of quantification (ULOQ) at ~3 × 10⁷ bacteria/mL, anda linearity R² = 0.976. The total time-to-results for detection and quantification was around 1.5 hours. Full article

(This article belongs to the Special Issue Lab on a Chip Technology for Pathogen Detection and Disease Diagnosis)

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20 pages, 5110 KiB

Open AccessArticle

FPGA Correlator for Applications in Embedded Smart Devices

by Christopher H. Moore and Wei Lin

Biosensors 2022, 12(4), 236; https://doi.org/10.3390/bios12040236 - 12 Apr 2022

Cited by 5 | Viewed by 3986

Abstract

Correlation has a variety of applications that require signal processing. However, it is computationally intensive, and software correlators require high-performance processors for real-time data analysis. This is a challenge for embedded devices because of the limitation of computing resources. Hardware correlators that use [...] Read more.

Correlation has a variety of applications that require signal processing. However, it is computationally intensive, and software correlators require high-performance processors for real-time data analysis. This is a challenge for embedded devices because of the limitation of computing resources. Hardware correlators that use Field Programmable Gate Array (FPGA) technology can significantly boost computational power and bridge the gap between the need for high-performance computing and the limited processing power available in embedded devices. This paper presents a detailed FPGA-based correlator design at the register level along with the open-source Very High-Speed Integrated Circuit Hardware Description Language (VHDL) code. It includes base modules for linear and multi-tau correlators of varying sizes. Every module implements a simple and unified data interface for easy integration with standard and publicly available FPGA modules. Eighty-lag linear and multi-tau correlators were built for validation of the design. Three input data sets—constant signal, pulse signal, and sine signal—were used to test the accuracy of the correlators. The results from the FPGA correlators were compared against the outputs of equivalent software correlators and validated with the corresponding theoretical values. The FPGA correlators returned results identical to those from the software references for all tested data sets and were proven to be equivalent to their software counterparts. Their computation speed is at least 85,000 times faster than the software correlators running on a Xilinx MicroBlaze processor. The FPGA correlator can be easily implemented, especially on System on a Chip (SoC) integrated circuits that have processor cores and FPGA fabric. It is the ideal component for device-on-chip solutions in biosensing. Full article

(This article belongs to the Special Issue Device-on-Chip Application in Biomedical Engineering)

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2 pages, 165 KiB

Open AccessEditorial

Non-Invasive Breath Analysis for Disease Screening and Diagnoses

by Hyun Jin Jung and Ronny Priefer

Biosensors 2022, 12(4), 235; https://doi.org/10.3390/bios12040235 - 12 Apr 2022

Cited by 1 | Viewed by 2594

Abstract

Lower respiratory infections are a deadly communicable disease ranked as the fourth leading cause of death globally, with nearly 2 [...] Full article

(This article belongs to the Special Issue Non-invasive Medical Devices for Detection and Monitoring within Healthcare)

11 pages, 3816 KiB

Open AccessEditor’s ChoiceArticle

An Artificial Intelligence-Enhanced Blood Pressure Monitor Wristband Based on Piezoelectric Nanogenerator

by Puchuan Tan, Yuan Xi, Shengyu Chao, Dongjie Jiang, Zhuo Liu, Yubo Fan and Zhou Li

Biosensors 2022, 12(4), 234; https://doi.org/10.3390/bios12040234 - 11 Apr 2022

Cited by 37 | Viewed by 6870

Abstract

Hypertensive patients account for about 16% to 37% of the global population, and about 9.4 million people die each year from hypertension and its complications. Blood pressure is an important indicator for diagnosing hypertension. Currently, blood pressure measurement methods are mainly based on [...] Read more.

Hypertensive patients account for about 16% to 37% of the global population, and about 9.4 million people die each year from hypertension and its complications. Blood pressure is an important indicator for diagnosing hypertension. Currently, blood pressure measurement methods are mainly based on mercury sphygmomanometers in hospitals or electronic sphygmomanometers at home. However, people’s blood pressure changes with time, and using only the blood pressure value at the current moment to judge hypertension may cause misdiagnosis. Continuous blood pressure measurement can monitor sudden increases in blood pressure, and can also provide physicians with long-term continuous blood pressure changes as a diagnostic reference. In this article, we design an artificial intelligence-enhanced blood pressure monitoring wristband. The wristband’s sensors are based on piezoelectric nanogenerators, with a high signal-to-noise ratio of 29.7 dB. Through the transformer deep learning model, the wristband can predict blood pressure readings, and the loss value is lower than 4 mmHg. By wearing this blood pressure monitoring wristband, we realized three days of continuous blood pressure monitoring of the subjects. The blood pressure monitoring wristband is lightweight, has profound significance for the prevention and treatment of hypertension, and has wide application prospects in medical, military, aerospace and other fields. Full article

(This article belongs to the Special Issue Self-Powered Flexible Biosensors and Electronic Skin)

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12 pages, 1816 KiB

Open AccessArticle

A Novel Full-length IgG Recombinant Antibody Highly Specific to Clothianidin and Its Application in Immunochromatographic Assay

by Yunyun Chang, Yang Chen, Shasha Jiao, Xinying Lu, Yihua Fang, Yihua Liu, Ying Zhao, Xiuping Zhan, Guonian Zhu and Yirong Guo

Biosensors 2022, 12(4), 233; https://doi.org/10.3390/bios12040233 - 11 Apr 2022

Cited by 5 | Viewed by 2478

Abstract

The toxicity of clothianidin to non-target organisms has gradually attracted world-wide attention. It is essential to develop reliable methods for the on-site detection of clothianidin residue. In this study, analogue-based heterologous ic-ELISAs were designed to rapidly screen desirable hybridomas, which could [...] Read more.

The toxicity of clothianidin to non-target organisms has gradually attracted world-wide attention. It is essential to develop reliable methods for the on-site detection of clothianidin residue. In this study, analogue-based heterologous ic-ELISAs were designed to rapidly screen desirable hybridomas, which could be used for the construction of recombinant antibodies (RAbs) against clothianidin. Based on the antibody variable region genes, two full-length IgG RAbs (1F7-RAb and 5C3-RAb) were produced by the mammalian cell expression system. The performance of the two RAbs was characterized and compared by heterologous ic-ELISAs and non-competitive surface plasmon resonance (SPR) assays. Using heterologous ic-ELISAs, the 1F7-RAb exhibited highly specific and sensitive recognition to clothianidin with an IC₅₀ of 4.62 μg/L, whereas the 5C3-RAb could bind to both clothianidin and dinotefuran. The results of the non-competitive SPR assay further verified that the 1F7-RAb had a higher specificity and affinity to clothianidin than the 5C3-RAb. Finally, a gold immunochromatographic assay based on the novel antibody, 1F7-RAb, was developed for rapid detection of clothianidin with high sensitivity (visual detection limit of 2.5 μg/L), specificity, and good reproducibility, which can be used as an effective supervision tool for clothianidin residue in agricultural and environmental samples. Full article

(This article belongs to the Special Issue Immunosensors and Immunoassays for Environmental, Agricultural and Food Safety Applications)

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11 pages, 891 KiB

Open AccessArticle

A Portable Nanoprobe for Rapid and Sensitive Detection of SARS-CoV-2 S1 Protein

by Hani A. Alhadrami, Ghadeer A. R. Y. Suaifan and Mohammed M. Zourob

Biosensors 2022, 12(4), 232; https://doi.org/10.3390/bios12040232 - 11 Apr 2022

Cited by 10 | Viewed by 3203

Abstract

Simple, timely, and precise detection of SARS-CoV-2 in clinical samples and contaminated surfaces aids in lowering attendant morbidity/mortality related to this infectious virus. Currently applied diagnostic techniques depend on a timely laboratory report following PCR testing. However, the application of these tests is [...] Read more.

Simple, timely, and precise detection of SARS-CoV-2 in clinical samples and contaminated surfaces aids in lowering attendant morbidity/mortality related to this infectious virus. Currently applied diagnostic techniques depend on a timely laboratory report following PCR testing. However, the application of these tests is associated with inherent shortcomings due to the need for trained personnel, long-time centralized laboratories, and expensive instruments. Therefore, there is an interest in developing biosensing diagnostic frontiers that can help in eliminating these shortcomings with a relatively economical, easy-to-use, well-timed, precise and sensitive technology. This study reports the development of fabricated Q-tips designed to qualitatively and semi-quantitatively detect SARS-CoV-2 in clinical samples and contaminated non-absorbable surfaces. This colorimetric sensor is engineered to sandwich SARS-CoV-2 spike protein between the lactoferrin general capturing agent and the complementary ACE2-labeled receptor. The ACE2 receptor is decorated with an orange-colored polymeric nanoparticle to generate an optical visual signal upon pairing with the SARS-CoV-2 spike protein. This colorimetric change of the Q-tip testing zone from white to orange confirms a positive result. The visual detection limit of the COVID-19 engineered colorimetric Q-tip sensor was 100 pfu/mL within a relatively short turnaround time of 5 min. The linear working range of quantitation was 10³–10⁸ pfu/mL. The engineered sensor selectively targeted SARS-CoV-2 spike protein and did not bind to another coronavirus such as MERS-CoV, Flu A, or Flu B present on the contaminated surface. This novel detection tool is relatively cheap to produce and suitable for onsite detection of COVID-19 infection. Full article

(This article belongs to the Special Issue Microfluidics, Bioelectronics, and MEMS-Based Devices for Diagnostics and Biomedical Application)

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11 pages, 1689 KiB

Open AccessArticle

Ni Nanoparticles Embedded Ti₃C₂T_x-MXene Nanoarchitectures for Electrochemical Sensing of Methylmalonic Acid

by Jai Kumar, Razium Ali Soomro, Rana R. Neiber, Nazeer Ahmed, Shymaa S. Medany, Munirah D. Albaqami and Ayman Nafady

Biosensors 2022, 12(4), 231; https://doi.org/10.3390/bios12040231 - 10 Apr 2022

Cited by 21 | Viewed by 3129

Abstract

MXenes-Ti₃C₂T_x, based on their versatile surface characteristics, has rapidly advanced as an interactive substrate to develop electrochemical sensors for clinical applications. Herein, Ni embedded Ti₃C₂T_x (MX−Ni) composites were prepared using a self-assembly [...] Read more.

MXenes-Ti₃C₂T_x, based on their versatile surface characteristics, has rapidly advanced as an interactive substrate to develop electrochemical sensors for clinical applications. Herein, Ni embedded Ti₃C₂T_x (MX−Ni) composites were prepared using a self-assembly approach where Ti₃C₂T_x sheets served as an interactive conductive substrate as well as a protective layer to nickel nanoparticles (Ni NPs), preventing their surface oxidation and aggregation. The composite displayed a cluster-like morphology with an intimate interfacial arrangement between Ni, Ti₃C₂T_x and Ti₃C₂T_x-derived TiO₂. The configuration of MX−Ni into an electrochemical sensor realized a robust cathodic reduction current against methylmalonic acid (MMA), a biomarker to vitamin B12 deficiency. The synergism of Ni NPs strong redox characteristics with conductive Ti₃C₂T_x enabled sensitive signal output in wide detection ranges of 0.001 to 0.003 µM and 0.0035 to 0.017 µM and a detection sensitivity down to 0.12 pM of MMA. Importantly, the sensor demonstrated high signal reproducibility and excellent operational capabilities for MMA in a complex biological matrix such as human urine samples. Full article

(This article belongs to the Special Issue Nanostructured 2D Materials in Biosensing)

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16 pages, 1617 KiB

Open AccessReview

Time Domain (TD) Proton NMR Analysis of the Oxidative Safety and Quality of Lipid-Rich Foods

by Tatiana Osheter, Charles Linder and Zeev Wiesman

Biosensors 2022, 12(4), 230; https://doi.org/10.3390/bios12040230 - 9 Apr 2022

Cited by 6 | Viewed by 3092

Abstract

Food safety monitoring is highly important due to the generation of unhealthy components within many food products during harvesting, processing, storage, transportation and cooking. Current technologies for food safety analysis often require sample extraction and the modification of the complex chemical and morphological [...] Read more.

Food safety monitoring is highly important due to the generation of unhealthy components within many food products during harvesting, processing, storage, transportation and cooking. Current technologies for food safety analysis often require sample extraction and the modification of the complex chemical and morphological structures of foods, and are either time consuming, have insufficient component resolution or require costly and complex instrumentation. In addition to the detection of unhealthy chemical toxins and microbes, food safety needs further developments in (a) monitoring the optimal nutritional compositions in many different food categories and (b) minimizing the potential chemical changes of food components into unhealthy products at different stages from food production until digestion. Here, we review an efficient methodology for overcoming the present analytical limitations of monitoring a food’s composition, with an emphasis on oxidized food components, such as polyunsaturated fatty acids, in complex structures, including food emulsions, using compact instruments for simple real-time analysis. An intelligent low-field proton NMR as a time domain (TD) NMR relaxation sensor technology for the monitoring of T₂ (spin-spin) and T₁ (spin-lattice) energy relaxation times is reviewed to support decision-making by producers, retailers and consumers in regard to food safety and nutritional value during production, shipping, storage and consumption. Full article

(This article belongs to the Special Issue Sensors for Food Safety)

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9 pages, 1925 KiB

Open AccessArticle

Validation of the Application of Solid Contact Ion-Selective Electrode for Off-Body Sweat Ion Monitoring

by Huixin Liu, Zhen Gu, Yuan Liu, Xinxin Xiao and Guangli Xiu

Biosensors 2022, 12(4), 229; https://doi.org/10.3390/bios12040229 - 9 Apr 2022

Cited by 4 | Viewed by 2976

Abstract

The solid contact ion-selective electrode (ISE) is a promising skin-interfaced monitoring system for sweat ions. Despite a growing number of on-body usages of ISE with fancy new materials and device fabrications, there are very few reports attempting to validate ISE results with a [...] Read more.

The solid contact ion-selective electrode (ISE) is a promising skin-interfaced monitoring system for sweat ions. Despite a growing number of on-body usages of ISE with fancy new materials and device fabrications, there are very few reports attempting to validate ISE results with a gold standard technique. For this purpose, this work uses inductively coupled plasma-optical emission spectrometry (ICP-OES) as a reference technique to conduct a direct evaluation of the sweat sodium and potassium ion levels obtained by ISE in an off-body approach. Eight healthy male subjects were recruited to collect exercise-induced sweat. It was found that sweat sodium and potassium ions present a rather wide concentration range. The sweat sodium concentration did not vary greatly in an exercise period of half an hour, while the sweat potassium concentration typically decreased with exercise. Mineral drink intake had no clear impact on the sweat sodium level, but increased the sweat potassium level. A paired t-test and mean absolute relative difference (MARD) analysis, a method typically used for evaluating the performance of glucometers, was employed to compare the results of ISE and ICP-OES. The statistical analysis validated the feasibility of ISE for measuring sweat ions, although better accuracy is required. Our data suggests that overweight subjects are likely to possess a higher sweat sodium level. Full article

(This article belongs to the Section Biosensors and Healthcare)

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17 pages, 5668 KiB

Open AccessArticle

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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