Nanomaterials

12 pages, 2777 KiB

Open AccessArticle

The Antibacterial Effect of Silver Nanoparticles on Staphylococcus Epidermidis Strains with Different Biofilm-Forming Ability

by Denis Swolana, Małgorzata Kępa, Danuta Idzik, Arkadiusz Dziedzic, Agata Kabała-Dzik, Tomasz J. Wąsik and Robert D. Wojtyczka

Nanomaterials 2020, 10(5), 1010; https://doi.org/10.3390/nano10051010 - 25 May 2020

Cited by 23 | Viewed by 4081

Abstract

Among many infectious diseases, infections caused by pathogens of Staphylococcus species exert a substantial influence upon human health, mainly due to their continuous presence on human skin and mucous membranes. For that reason, an intensive search for new, effective anistaphyloccocal agents can currently [...] Read more.

Among many infectious diseases, infections caused by pathogens of Staphylococcus species exert a substantial influence upon human health, mainly due to their continuous presence on human skin and mucous membranes. For that reason, an intensive search for new, effective anistaphyloccocal agents can currently be observed worldwide. In recent years, there has been growing interest in nanoparticles, as compounds with potential antibacterial effect. The antibacterial activity of silver containing substances has been well recognized, but thoughtful studies focused on the effect of silver nanoparticles on bacterial biofilm are scarce. The aim of this study was to assess the influence of silver nanoparticles (AgNPs) with particle sizes in the range between 10 and 100 nm, and a concentration range from 1 to 10 µg/mL, upon Staphylococcus epidermidis strains with different biofilm-forming abilities (BFAs). The studies revealed the highest level of antimicrobial activity for AgNPs in relation to S. epidermidis strains with BFA, and what is more, the observed effect was proportional to the increasing particles’ size, and strains not forming biofilm were more susceptible to silver nanoparticles with the smallest examined size, which was 10 nm. Full article

(This article belongs to the Special Issue Antibacterial Activity of Nanoparticles)

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13 pages, 3771 KiB

Open AccessArticle

Controlling the Structures, Flexibility, Conductivity Stability of Three-Dimensional Conductive Networks of Silver Nanoparticles/Carbon-Based Nanomaterials with Nanodispersion and their Application in Wearable Electronic Sensors

by Chih-Wei Chiu, Jia-Wun Li, Chen-Yang Huang, Shun-Siang Yang, Yu-Chian Soong, Chih-Lung Lin, Jimmy Chi-Min Lee, William Anderson Lee Sanchez, Chih-Chia Cheng and Maw-Cherng Suen

Nanomaterials 2020, 10(5), 1009; https://doi.org/10.3390/nano10051009 - 25 May 2020

Cited by 25 | Viewed by 3933

Abstract

This research has successfully synthesized highly flexible and conductive nanohybrid electrode films. Nanodispersion and stabilization of silver nanoparticles (AgNPs) were achieved via non-covalent adsorption and with an organic polymeric dispersant and inorganic carbon-based nanomaterials—nano-carbon black (CB), carbon nanotubes (CNT), and graphene oxide (GO). [...] Read more.

This research has successfully synthesized highly flexible and conductive nanohybrid electrode films. Nanodispersion and stabilization of silver nanoparticles (AgNPs) were achieved via non-covalent adsorption and with an organic polymeric dispersant and inorganic carbon-based nanomaterials—nano-carbon black (CB), carbon nanotubes (CNT), and graphene oxide (GO). The new polymeric dispersant—polyisobutylene-b-poly(oxyethylene)-b-polyisobutylene (PIB-POE-PIB) triblock copolymer—could stabilize AgNPs. Simultaneously, this stabilization was conducted through the addition of mixed organic/inorganic dispersants based on zero- (0D), one- (1D), and two-dimensional (2D) nanomaterials, namely CB, CNT, and GO. Furthermore, the dispersion solution was evenly coated/mixed onto polymeric substrates, and the products were heated. As a result, highly conductive thin-film materials (with a surface electrical resistance of approximately 10⁻² Ω/sq) were eventually acquired. The results indicated that 2D carbon-based nanomaterials (GO) could stabilize AgNPs more effectively during their reductNion and, hence, generate particles with the smallest sizes, as the COO⁻ functional groups of GO are evenly distributed. The optimal AgNPs/PIB-POE-PIB/GO ratio was 20:20:1. Furthermore, the flexible electrode layers were successfully manufactured and applied in wearable electronic sensors to generate electrocardiograms (ECGs). ECGs were, thereafter, successfully obtained. Full article

(This article belongs to the Special Issue Synthesis and Applications of Graphite Oxide and Graphene Oxide Nanocomposites)

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28 pages, 845 KiB

Open AccessReview

Protein Supramolecular Structures: From Self-Assembly to Nanovaccine Design

by Ximena Zottig, Mélanie Côté-Cyr, Dominic Arpin, Denis Archambault and Steve Bourgault

Nanomaterials 2020, 10(5), 1008; https://doi.org/10.3390/nano10051008 - 25 May 2020

Cited by 45 | Viewed by 6411

Abstract

Life-inspired protein supramolecular assemblies have recently attracted considerable attention for the development of next-generation vaccines to fight against infectious diseases, as well as autoimmune diseases and cancer. Protein self-assembly enables atomic scale precision over the final architecture, with a remarkable diversity of structures [...] Read more.

Life-inspired protein supramolecular assemblies have recently attracted considerable attention for the development of next-generation vaccines to fight against infectious diseases, as well as autoimmune diseases and cancer. Protein self-assembly enables atomic scale precision over the final architecture, with a remarkable diversity of structures and functionalities. Self-assembling protein nanovaccines are associated with numerous advantages, including biocompatibility, stability, molecular specificity and multivalency. Owing to their nanoscale size, proteinaceous nature, symmetrical organization and repetitive antigen display, protein assemblies closely mimic most invading pathogens, serving as danger signals for the immune system. Elucidating how the structural and physicochemical properties of the assemblies modulate the potency and the polarization of the immune responses is critical for bottom-up design of vaccines. In this context, this review briefly covers the fundamentals of supramolecular interactions involved in protein self-assembly and presents the strategies to design and functionalize these assemblies. Examples of advanced nanovaccines are presented, and properties of protein supramolecular structures enabling modulation of the immune responses are discussed. Combining the understanding of the self-assembly process at the molecular level with knowledge regarding the activation of the innate and adaptive immune responses will support the design of safe and effective nanovaccines. Full article

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

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18 pages, 9371 KiB

Open AccessArticle

Synthesis and Memristor Effect of a Forming-Free ZnO Nanocrystalline Films

by Roman V. Tominov, Zakhar E. Vakulov, Vadim I. Avilov, Daniil A. Khakhulin, Aleksandr A. Fedotov, Evgeny G. Zamburg, Vladimir A. Smirnov and Oleg A. Ageev

Nanomaterials 2020, 10(5), 1007; https://doi.org/10.3390/nano10051007 - 25 May 2020

Cited by 26 | Viewed by 3898

Abstract

We experimentally investigated the effect of post-growth annealing on the morphological, structural, and electrophysical parameters of nanocrystalline ZnO films fabricated by pulsed laser deposition. The influence of post-growth annealing modes on the electroforming voltage and the resistive switching effect in ZnO nanocrystalline films [...] Read more.

We experimentally investigated the effect of post-growth annealing on the morphological, structural, and electrophysical parameters of nanocrystalline ZnO films fabricated by pulsed laser deposition. The influence of post-growth annealing modes on the electroforming voltage and the resistive switching effect in ZnO nanocrystalline films is investigated. We demonstrated that nanocrystalline zinc oxide films, fabricated at certain regimes, show the electroforming-free resistive switching. It was shown, that the forming-free nanocrystalline ZnO film demonstrated a resistive switching effect and switched at a voltage 1.9 ± 0.2 V from 62.42 ± 6.47 (R_HRS) to 0.83 ± 0.06 kΩ (R_LRS). The influence of ZnO surface morphology on the resistive switching effect is experimentally investigated. It was shown, that the ZnO nanocrystalline film exhibits a stable resistive switching effect, which is weakly dependent on its nanoscale structure. The influence of technological parameters on the resistive switching effect in a forming-free ZnO nanocrystalline film is investigated. The results can be used for fabrication of new-generation micro- and nanoelectronics elements, including random resistive memory (ReRAM) elements for neuromorphic structures based on forming-free ZnO nanocrystalline films. Full article

(This article belongs to the Special Issue ZnO Based Nanostructures: Synthesis, Characterization and Applications)

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16 pages, 6408 KiB

Open AccessArticle

The Structural, Electronic, and Optical Properties of Ge/Si Quantum Wells: Lasing at a Wavelength of 1550 nm

by Hongqiang Li, Jianing Wang, Jinjun Bai, Shanshan Zhang, Sai Zhang, Yaqiang Sun, Qianzhi Dou, Mingjun Ding, Youxi Wang, Dan Qu, Jilin Du, Chunxiao Tang, Enbang Li and Joan Daniel Prades

Nanomaterials 2020, 10(5), 1006; https://doi.org/10.3390/nano10051006 - 25 May 2020

Cited by 2 | Viewed by 4170

Abstract

The realization of a fully integrated group IV electrically driven laser at room temperature is an essential issue to be solved. We introduced a novel group IV side-emitting laser at a wavelength of 1550 nm based on a 3-layer Ge/Si quantum well (QW). [...] Read more.

The realization of a fully integrated group IV electrically driven laser at room temperature is an essential issue to be solved. We introduced a novel group IV side-emitting laser at a wavelength of 1550 nm based on a 3-layer Ge/Si quantum well (QW). By designing this scheme, we showed that the structural, electronic, and optical properties are excited for lasing at 1550 nm. The preliminary results show that the device can produce a good light spot shape convenient for direct coupling with the waveguide and single-mode light emission. The laser luminous power can reach up to 2.32 mW at a wavelength of 1550 nm with a 300-mA current. Moreover, at room temperature (300 K), the laser can maintain maximum light power and an ideal wavelength (1550 nm). Thus, this study provides a novel approach to reliable, efficient electrically pumped silicon-based lasers. Full article

(This article belongs to the Special Issue Nano Devices and Nano Sensors)

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14 pages, 3181 KiB

Open AccessArticle

Coverage Layer Phase Composition-Dependent Photoactivity of One-Dimensional TiO₂–Bi₂O₃ Composites

by Yuan-Chang Liang and Kai-Jen Chiang

Nanomaterials 2020, 10(5), 1005; https://doi.org/10.3390/nano10051005 - 25 May 2020

Cited by 16 | Viewed by 2846

Abstract

TiO₂–Bi₂O₃ composite rods were synthesized by combining hydrothermal growth of rutile TiO₂ rod templates and sputtering deposition of Bi₂O₃ thin films. The TiO₂–Bi₂O₃ composite rods with β-Bi₂O [...] Read more.

TiO₂–Bi₂O₃ composite rods were synthesized by combining hydrothermal growth of rutile TiO₂ rod templates and sputtering deposition of Bi₂O₃ thin films. The TiO₂–Bi₂O₃ composite rods with β-Bi₂O₃ phase and α/β-Bi₂O₃ dual-phase decoration layers were designed, respectively, via in situ radio-frequency magnetron sputtering growth and post-annealing procedures in ambient air. The crystal structure, surface morphology, and photo-absorption performances of the pristine TiO₂ rods decorated with various Bi₂O₃ phases were investigated. The crystal structure analysis reveals that the crystalline TiO₂–Bi₂O₃ rods contained β-Bi₂O₃ and α/β-Bi₂O₃ crystallites were separately formed on the TiO₂ rod templates with different synthesis approaches. The morphology analysis demonstrates that the β-Bi₂O₃ coverage layer on the crystalline rutile TiO₂ rods showed flat layer morphology; however, the surface morphology of the α/β-Bi₂O₃ dual-phase coverage layer on the TiO₂ rods exhibited a sheet-like feature. The results of photocatalytic decomposition towards methyl orange dyes show that the substantially improved photoactivity of the rutile TiO₂ rods was achieved by decorating a thin sheet-like α/β-Bi₂O₃ coverage layer. The effectively photoinduced charge separation efficiency in the stepped energy band configuration in the composite rods made from the TiO₂ and α/β-Bi₂O₃ explained their markedly improved photoactivity. The TiO₂-α/β-Bi₂O₃ composite rods are promising for use as photocatalysts and photoelectrodes. Full article

(This article belongs to the Special Issue Hybrid Nanomaterials Synthesis and Application)

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17 pages, 3987 KiB

Open AccessArticle

Graphene Decorated Zinc Oxide and Curcumin to Disinfect the Methicillin-Resistant Staphylococcus aureus

by Mohammad Oves, Mohd. Ahmar Rauf, Mohammad Omaish Ansari, Aftab Aslam Parwaz Khan, Huda A Qari, Mohamed F. Alajmi, Samaresh Sau and Arun K Iyer

Nanomaterials 2020, 10(5), 1004; https://doi.org/10.3390/nano10051004 - 25 May 2020

Cited by 32 | Viewed by 4376 | Correction

Abstract

Sometimes, life-threatening infections are initiated by the biofilm formation facilitated at the infection site by the drug-resistant bacteria Staphylococcus aureus. The aggregation of the same type of bacteria leads to biofilm formation on the delicate tissue, dental plaque, and skin. In the [...] Read more.

Sometimes, life-threatening infections are initiated by the biofilm formation facilitated at the infection site by the drug-resistant bacteria Staphylococcus aureus. The aggregation of the same type of bacteria leads to biofilm formation on the delicate tissue, dental plaque, and skin. In the present investigation, a Graphene (Gr)-based nano-formulation containing Curcumin (C.C.M.) and Zinc oxide nanoparticles (ZnO-NPs) showed a wide range of anti-microbial activity against Methicillin-resistant Staphylococcus aureus (MRSA) biofilm and demonstrated the anti-microbial mechanism of action. The anti-microbial effect of GrZnO nanocomposites, i.e., GrZnO-NCs, suggests that the integrated graphene-based nanocomposites effectively suppressed both sensitive as well as MRSA ATCC 43300 and BAA-1708 isolates. The S. aureus inhibitory effect of GrZnO-NCs improved >5-fold when combined with C.C.M., and demonstrated a M.I.C. of 31.25 µg/mL contrasting with the GrZnO-NCs or C.C.M. alone having M.I.C. value of 125 µg/mL each. The combination treatment of GrZnO-NCs or C.C.M. inhibited the M.R.S.A. topical dermatitis infection in a mice model with a significant decrease in the CFU count to ~64%. Interestingly, the combination of C.C.M. and GrZnO-NCs damaged the bacterial cell wall structure, resulting in cytoplasm spillage, thereby diminishing their metabolism. Thus, owing to the ease of synthesis and highly efficient anti-microbial properties, the present graphene-based curcumin nano-formulations can cater to a new treatment methodology against M.R.S.A. Full article

(This article belongs to the Section Biology and Medicines)

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13 pages, 2032 KiB

Open AccessArticle

Antifungal Potential of Nanostructured Crystalline Copper and Its Oxide Forms

by Auriane Fifame Oussou-Azo, Tomoki Nakama, Masayuki Nakamura, Taiki Futagami and Mun’delanji Catherine M. Vestergaard

Nanomaterials 2020, 10(5), 1003; https://doi.org/10.3390/nano10051003 - 24 May 2020

Cited by 55 | Viewed by 4328

Abstract

Copper has been used as an antimicrobial agent for over a century and is now being added to commercial fungicides. Nanomaterials have attracted much attention due to the special properties they have over their bulk form. We studied nanostructured copper (Cu-NPs), investigating the [...] Read more.

Copper has been used as an antimicrobial agent for over a century and is now being added to commercial fungicides. Nanomaterials have attracted much attention due to the special properties they have over their bulk form. We studied nanostructured copper (Cu-NPs), investigating the potential for improved antifungal properties derived from its special properties and studied any effect that the oxidation of copper (CuO-NPs) may have. We conducted this research against Colletotrichum gloeoesporioides, a devastating pathogen to plants/crops worldwide. Research on the effects of copper on this fungus are limited. Our studies showed that nanoforms of copper had significant antifungal activities, with Cu-NPs offering the most sustainable efficacy and was more effective than its oxidative form (CuO-NPs). Scanning Electron Microscopy (SEM) images of the treated pathogen show that the hyphae had a swollen appearance, lost their filamentous structure, and the mycelia had a powder-like structure, indicating the probable destruction of the hyphal tubular cell wall. X-ray Difractogram (XRD) outputs showed substantial changes in the physical characteristics of the Cu-NPs after interaction with the fungus. This is the first report to demonstrate chemo-physical changes in the metal compounds, opening new insights for further studies on the mechanism of copper’s antifungal properties. Full article

(This article belongs to the Special Issue Bionanotechnology)

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14 pages, 2230 KiB

Open AccessArticle

CuFeAl Nanocomposite Catalysts for Coal Combustion in Fluidized Bed

by Aleksandr V. Fedorov, Nikolay A. Yazykov, Olga A. Bulavchenko, Andrey A. Saraev, Vasily V. Kaichev and Vadim A. Yakovlev

Nanomaterials 2020, 10(5), 1002; https://doi.org/10.3390/nano10051002 - 24 May 2020

Cited by 13 | Viewed by 3067

Abstract

A method of oil-drop granulation was suggested for the preparation of spherical CuFeAl nanocomposite catalysts. The catalysts were characterized by a set of physicochemical methods (X-ray diffraction, temperature-programmed reduction by H₂, low-temperature nitrogen adsorption, crushing strength) and tested in the oxidation [...] Read more.

A method of oil-drop granulation was suggested for the preparation of spherical CuFeAl nanocomposite catalysts. The catalysts were characterized by a set of physicochemical methods (X-ray diffraction, temperature-programmed reduction by H₂, low-temperature nitrogen adsorption, crushing strength) and tested in the oxidation of CO and burning of brown coal in a fluidized bed. It was found that the catalysts have high mechanical strength (16.2 MPa), and their catalytic properties in the oxidation of CO are comparable to the characteristics of industrial Cr-containing catalysts. It was shown that the addition of pseudoboehmite at the stage of drop formation contributes to the production of uniform spherical high-strength granules and facilitates the stabilization of the phase state of the active component. The use of CuFeAl nanocomposite catalysts for the burning of brown coal provides a low emission of CO (600 ppm) and NO_x (220 ppm) and a high degree of coal burnout (95%), which are close to those of the industrial Cr-containing catalysts (emission of CO is 700 ppm, NO_x—230 ppm, and degree of coal burnout is 95%). Full article

(This article belongs to the Special Issue Synthesis of Nanocomposites and Catalysis Applications)

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21 pages, 6715 KiB

Open AccessArticle

Reduced Graphene Oxide Nanosheet-Decorated Copper Oxide Nanoparticles: A Potent Antifungal Nanocomposite against Fusarium Root Rot and Wilt Diseases of Tomato and Pepper Plants

by Sozan E. El-Abeid, Yosra Ahmed, José-Antonio Daròs and Mohamed A. Mohamed

Nanomaterials 2020, 10(5), 1001; https://doi.org/10.3390/nano10051001 - 24 May 2020

Cited by 62 | Viewed by 6171

Abstract

Sustainable use of nanotechnology in crop protection requires an understanding of the plant’s life cycle, potential toxicological impacts of nanomaterials and their mechanism of action against the target pathogens. Herein, we show some properties of a candidate antifungal nanocomposite made from copper oxide [...] Read more.

Sustainable use of nanotechnology in crop protection requires an understanding of the plant’s life cycle, potential toxicological impacts of nanomaterials and their mechanism of action against the target pathogens. Herein, we show some properties of a candidate antifungal nanocomposite made from copper oxide (CuO; otherwise an essential soil nutrient) nanoparticles (NPs), with definite size and shape, decorating the surface of reduced graphene oxide (rGO) nanosheets. The successful preparation of the rGO-CuO NPs was confirmed by spectroscopic and microscopic analyses, and its antifungal activity against wild strains of Fusarium oxysporum affecting tomato and pepper plants was successfully confirmed. A comparative analysis in vitro indicated that this nanocomposite had higher antifungal activity at only 1 mg/L than the conventional fungicide Kocide 2000 at 2.5 g/L. Further investigation suggested that rGO-CuO NPs creates pits and pores on the fungal cell membranes inducing cell death. In planta results indicated that only 1 mg/L from the nanocomposite is required to reduce Fusarium wilt and root rot diseases severity below 5% for tomato and pepper plants without any phytotoxicity for about 70 days. Comparatively, 2.5 g/L of Kocide 2000 are required to achieve about 30% disease reduction in both plants. The present study contributes to the concept of agro-nanotechnology, showing the properties of a novel ecofriendly and economic nanopesticide for sustainable plant protection. Full article

(This article belongs to the Section Biology and Medicines)

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10 pages, 2205 KiB

Open AccessArticle

Detection of Aflatoxin B₁ Based on a Porous Anodized Aluminum Membrane Combined with Surface-Enhanced Raman Scattering Spectroscopy

by Yanting Feng, Lei He, Ling Wang, Rijian Mo, Chunxia Zhou, Pengzhi Hong and Chengyong Li

Nanomaterials 2020, 10(5), 1000; https://doi.org/10.3390/nano10051000 - 24 May 2020

Cited by 26 | Viewed by 3385

Abstract

An Aflatoxin B₁ (AFB₁) biosensor was fabricated via an Ag nanoparticles assembly on the surface of a porous anodized aluminum (PAA) membrane. First, the Raman reporter 4-Aminothiophenol (4-ATP) and DNA (partially complementary to AFB₁ aptamer) were attached to the [...] Read more.

An Aflatoxin B₁ (AFB₁) biosensor was fabricated via an Ag nanoparticles assembly on the surface of a porous anodized aluminum (PAA) membrane. First, the Raman reporter 4-Aminothiophenol (4-ATP) and DNA (partially complementary to AFB₁ aptamer) were attached to the surface of Ag nanoparticles (AgNPs) by chemical bonding to form a 4-ATP-AgNPs-DNA complex. Similarly, the surface of a PAA membrane was functionalized with an AFB₁ aptamer. Then, the PAA surface was functionalized with 4-ATP-AgNPs-DNA through base complementary pairing to form AgNPs-PAA sensor with a strong Raman signal. When AFB₁ was added, AgNPs would be detached from the PAA surface because of the specific binding between AFB₁ and the aptamer, resulting in a reduction in Raman signals. The detection limit of the proposed biosensor is 0.009 ng/mL in actual walnut and the linear range is 0.01–10 ng/mL. The sensor has good selectivity and repeatability; it can be applied to the rapid qualitative and quantitative detection of AFB₁. Full article

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13 pages, 231 KiB

Open AccessArticle

Reduction of Health Care-Associated Infections (HAIs) with Antimicrobial Inorganic Nanoparticles Incorporated in Medical Textiles: An Economic Assessment

by Finbarr Murphy, Anat Tchetchik and Irini Furxhi

Nanomaterials 2020, 10(5), 999; https://doi.org/10.3390/nano10050999 - 23 May 2020

Cited by 23 | Viewed by 4935

Abstract

Health care-associated infections (HAIs) affect millions of patients annually with up to 80,000 affected in Europe on any given day. This represents a significant societal and economic burden. Staff training, hand hygiene, patient identification and isolation and controlled antibiotic use are some of [...] Read more.

Health care-associated infections (HAIs) affect millions of patients annually with up to 80,000 affected in Europe on any given day. This represents a significant societal and economic burden. Staff training, hand hygiene, patient identification and isolation and controlled antibiotic use are some of the standard ways to reduce HAI incidence but this is time consuming and subject and subject to rigorous implementation. In addition, the lack of antimicrobial activity of some disinfectants against healthcare-associated pathogens may also affect the efficacy of disinfection practices. Textiles are an attractive substrate for pathogens because of contact with the human body with the attendant warmth and moisture. Textiles and surfaces coated with engineered nanomaterials (ENMs) have shown considerable promise in reducing the microbial burden on those surfaces. Studies have also shown that this antimicrobial affect can reduce the incidence of HAIs. For all of the promising research, there has been an absence of study on the economic effectiveness of ENM coated materials in a healthcare setting. This article examines the relative economic efficacy of ENM coated materials against an antiseptic approach. The goal is to establish the economic efficacy of the widespread usage of ENM coated materials in a healthcare setting. In the absence of detailed and segregated costs, benefits and control variables over at least cross sectional data or time series, an aggregated approach is warranted. This approach, while relying on some supposition allows for a comparison with similar data regarding standard treatment to reduce HAIs and provides a reasonable economic comparison. We find that while, relative to antiseptics, ENM coated textiles represent a significant clinical advantage, they can also offer considerable cost savings. Full article

(This article belongs to the Special Issue From Nanoinformatics to Nanomaterials Risk Assessment and Governance)

15 pages, 3611 KiB

Open AccessArticle

Development of Porous Titania Structure with Improved Photocatalytic Activity: Response Surface Modeling and Multi-Objective Optimization

by Elvira Mahu, Maria Ignat, Corneliu Cojocaru, Petrisor Samoila, Cristina Coromelci, Iuliean Asaftei and Valeria Harabagiu

Nanomaterials 2020, 10(5), 998; https://doi.org/10.3390/nano10050998 - 23 May 2020

Cited by 12 | Viewed by 2903

Abstract

Porous titania was successfully synthesized by an ultrasound-assisted sol-gel route. The synthesis process was empirically modeled and optimized using the response surface methodology (RSM). Input variables adopted for optimization dealt with the weight ratio of precursors (r) and the sonication time [...] Read more.

Porous titania was successfully synthesized by an ultrasound-assisted sol-gel route. The synthesis process was empirically modeled and optimized using the response surface methodology (RSM). Input variables adopted for optimization dealt with the weight ratio of precursors (r) and the sonication time (t), representing the used factors in the synthesis procedure. With regard to application, the synthesized TiO₂ samples were tested for the photodegradation of two water-soluble organic pollutants under UV–Vis irradiation. Optimal conditions for the efficient pollutants’ photodegradation were found to involve a precursors ratio of 3 and a sonication time of 60 min. Thus, the M5 sample prepared under the founded optimal conditions yielded the maximal removal efficiencies of 98.4% and 46.3% for the photodegradation of CR dye and 2,4-D herbicide, respectively. In addition, the photodegradation kinetics revealed the pseudo first-order rate constants, showing the photodegradation of CR (k₁ = 8.86 × 10⁻² min⁻¹) by M5 sample is about 1.3-fold faster than the photodegradation of 2,4-D pesticide (k₂ = 6.84 × 10⁻² min⁻¹). Full article

(This article belongs to the Special Issue 10th Anniversary of Nanomaterials—Recent Advances in Nanomaterials for Energy and Catalysis)

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14 pages, 4669 KiB

Open AccessArticle

Chlortetracycline-Functionalized Silver Nanoparticles as a Colorimetric Probe for Aminoglycosides: Ultrasensitive Determination of Kanamycin and Streptomycin

by Ganesh Dattatraya Saratale, Rijuta Ganesh Saratale, Gajanan Ghodake, Surendra Shinde, Dae-Young Kim, Abdullah A. Alyousef, Mohammed Arshad, Asad Syed, Deepak Pant and Han-Seung Shin

Nanomaterials 2020, 10(5), 997; https://doi.org/10.3390/nano10050997 - 22 May 2020

Cited by 25 | Viewed by 4694

Abstract

Aminoglycosides (AMGs) have been extensively used to treat infectious diseases caused by Gram-negative bacteria in livestock and humans. A selective and sensitive colorimetric probe for the determination of streptomycin and kanamycin was proposed based on chlortetracycline-coated silver nanoparticles (AgNPs–CTC) as the sensing element. [...] Read more.

Aminoglycosides (AMGs) have been extensively used to treat infectious diseases caused by Gram-negative bacteria in livestock and humans. A selective and sensitive colorimetric probe for the determination of streptomycin and kanamycin was proposed based on chlortetracycline-coated silver nanoparticles (AgNPs–CTC) as the sensing element. Almost all of the tested aminoglycoside antibiotics can rapidly induce the aggregation of AgNPs, along with a color change from yellow to orange/red. The selective detection of aminoglycoside antibiotics, including tobramycin, streptomycin, amikacin, gentamicin, neomycin, and kanamycin, with other types of antibiotics, can be achieved by ultraviolet (UV) spectroscopy. This developed colorimetric assay has ability to detect various AMGs using in-depth surface plasmon resonance (SPR) studies. With this determination of streptomycin and kanamycin was achieved at the picomolar level (pM) by using a UV–visible spectrophotometer. Under aqueous conditions, the linear range of the colorimetric sensor for streptomycin and kanamycin was 1000–1,1000 and 120–480 pM, respectively. The corresponding limit of detection was 2000 pM and 120 pM, respectively. Thus, the validated dual colorimetric and ratiometric method can find various analytical applications for the ultrasensitive and rapid detection of AMG antibiotics in water samples. Full article

(This article belongs to the Special Issue Probing Single Events at the Nanoscale)

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27 pages, 4096 KiB

Open AccessArticle

Improved Photocatalyzed Degradation of Phenol, as a Model Pollutant, over Metal-Impregnated Nanosized TiO₂

by S. Belekbir, M. El Azzouzi, A. El Hamidi, L. Rodríguez-Lorenzo, J. Arturo Santaballa and M. Canle

Nanomaterials 2020, 10(5), 996; https://doi.org/10.3390/nano10050996 - 22 May 2020

Cited by 26 | Viewed by 3838

Abstract

Photocatalyzed degradation of phenol in aqueous solution over surface impregnated TiO₂ (M = Cu, Cr, V) under UV-Vis (366 nm) and UV (254 nm) irradiation is described. Nanosized photocatalyts were prepared from TiO₂-P25 by wet impregnation, and characterized by X-ray [...] Read more.

Photocatalyzed degradation of phenol in aqueous solution over surface impregnated TiO₂ (M = Cu, Cr, V) under UV-Vis (366 nm) and UV (254 nm) irradiation is described. Nanosized photocatalyts were prepared from TiO₂-P25 by wet impregnation, and characterized by X-ray diffraction, X-ray fluorescence, transmission electron microscopy, UV-Vis diffuse reflectance spectroscopy, Raman spectroscopy, and adsorption studies. No oxide phases of the metal dopants were found, although their presence in the TiO₂-P25 lattice induces tensile strain in Cu-impregnated TiO₂-P25, whereas compressive strain in Cr- and V-impregnated TiO₂-P25. Experimental evidences support chemical and mechanical stability of the photocatalysts. Type IV N₂ adsorption–desorption isotherms, with a small H3 loop near the maximum relative pressure were observed. Metal surface impregnated photocatalysts are mesoporous with a similar surface roughness, and a narrow pore distribution around ca. 25 Å. They were chemically stable, showing no metal lixiviation. Their photocatalytic activity was followed by UV-Vis spectroscopy and HPLC–UV. A first order kinetic model appropriately fitted the experimental data. The fastest phenol degradation was obtained with M (0.1%)/TiO₂-P25, the reactivity order being Cu > V >> Cr > TiO₂-P25 under 366 nm irradiation, while TiO₂-P25 > Cu > V > Cr, when using 254 nm radiation. TOC removal under 366 nm irradiation for 300 min showed almost quantitative mineralization for all tested materials, while 254 nm irradiation for 60 min led to maximal TOC removal (ca. 30%). Photoproducts and intermediate photoproducts were identified by HPLC–MS, and appropriate reaction pathways are proposed. The energy efficiency of the process was analysed, showing UV lamps are superior to UVA lamps, and that the efficiency of the surface impregnated catalyst varies in the order Cu > V > Cr. Full article

(This article belongs to the Special Issue Application of Nanomaterials in Photocatalysis)

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17 pages, 2853 KiB

Open AccessArticle

Gold Nanoparticles Induce Oxidative Stress and Apoptosis in Human Kidney Cells

by Maria Enea, Eulália Pereira, Miguel Peixoto de Almeida, Ana Margarida Araújo, Maria de Lourdes Bastos and Helena Carmo

Nanomaterials 2020, 10(5), 995; https://doi.org/10.3390/nano10050995 - 22 May 2020

Cited by 55 | Viewed by 5392

Abstract

Gold nanoparticles (AuNPs) are highly attractive for biomedical applications. Therefore, several in vitro and in vivo studies have addressed their safety evaluation. Nevertheless, there is a lack of knowledge regarding their potential detrimental effect on human kidney. To evaluate this effect, AuNPs with [...] Read more.

Gold nanoparticles (AuNPs) are highly attractive for biomedical applications. Therefore, several in vitro and in vivo studies have addressed their safety evaluation. Nevertheless, there is a lack of knowledge regarding their potential detrimental effect on human kidney. To evaluate this effect, AuNPs with different sizes (13 nm and 60 nm), shapes (spheres and stars), and coated with 11-mercaptoundecanoic acid (MUA) or with sodium citrate, were synthesized, characterized, and their toxicological effects evaluated 24 h after incubation with a proximal tubular cell line derived from normal human kidney (HK-2). After exposure, viability was assessed by the MTT assay. Changes in lysosomal integrity, mitochondrial membrane potential (ΔΨm), reactive species (ROS/RNS), intracellular glutathione (total GSH), and ATP were also evaluated. Apoptosis was investigated through the evaluation of the activity of caspases 3, 8 and 9. Overall, the tested AuNPs targeted mainly the mitochondria in a concentration-dependent manner. The lysosomal integrity was also affected but to a lower extent. The smaller 13 nm nanospheres (both citrate- and MUA-coated) proved to be the most toxic among all types of AuNPs, increasing ROS production and decreasing mitochondrial membrane potential (p ≤ 0.01). For the MUA-coated 13 nm nanospheres, these effects were associated also to increased levels of total glutathione (p ≤ 0.01) and enhanced ATP production (p ≤ 0.05). Programmed cell death was detected through the activation of both extrinsic and intrinsic pathways (caspase 8 and 9) (p ≤ 0.05). We found that the larger 60 nm AuNPs, both nanospheres and nanostars, are apparently less toxic than their smaller counter parts. Considering the results herein presented, it should be taken into consideration that even if renal clearance of the AuNPs is desirable, since it would prevent accumulation and detrimental effects in other organs, a possible intracellular accumulation of AuNPs in kidneys can induce cell damage and later compromise kidney function. Full article

(This article belongs to the Special Issue Safety and Biocompatibility of Metallic Nanoparticles)

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8 pages, 2194 KiB

Open AccessArticle

Memristive and Synaptic Characteristics of Nitride-Based Heterostructures on Si Substrate

by Mehr Khalid Rahmani, Min-Hwi Kim, Fayyaz Hussain, Yawar Abbas, Muhammad Ismail, Kyungho Hong, Chandreswar Mahata, Changhwan Choi, Byung-Gook Park and Sungjun Kim

Nanomaterials 2020, 10(5), 994; https://doi.org/10.3390/nano10050994 - 22 May 2020

Cited by 21 | Viewed by 4194

Abstract

Brain-inspired artificial synaptic devices and neurons have the potential for application in future neuromorphic computing as they consume low energy. In this study, the memristive switching characteristics of a nitride-based device with two amorphous layers (SiN/BN) is investigated. We demonstrate the coexistence of [...] Read more.

Brain-inspired artificial synaptic devices and neurons have the potential for application in future neuromorphic computing as they consume low energy. In this study, the memristive switching characteristics of a nitride-based device with two amorphous layers (SiN/BN) is investigated. We demonstrate the coexistence of filamentary (abrupt) and interface (homogeneous) switching of Ni/SiN/BN/n⁺⁺-Si devices. A better gradual conductance modulation is achieved for interface-type switching as compared with filamentary switching for an artificial synaptic device using appropriate voltage pulse stimulations. The improved classification accuracy for the interface switching (85.6%) is confirmed and compared to the accuracy of the filamentary switching mode (75.1%) by a three-layer neural network (784 × 128 × 10). Furthermore, the spike-timing-dependent plasticity characteristics of the synaptic device are also demonstrated. The results indicate the possibility of achieving an artificial synapse with a bilayer SiN/BN structure. Full article

(This article belongs to the Section Nanophotonics Materials and Devices)

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17 pages, 3921 KiB

Open AccessArticle

Bifunctional Tm³⁺,Yb³⁺:GdVO₄@SiO₂ Core-Shell Nanoparticles in HeLa Cells: Upconversion Luminescence Nanothermometry in the First Biological Window and Biolabelling in the Visible

by Oleksandr Savchuk, Joan Josep Carvajal Marti, Concepción Cascales, Patricia Haro-Gonzalez, Francisco Sanz-Rodríguez, Magdalena Aguilo and Francesc Diaz

Nanomaterials 2020, 10(5), 993; https://doi.org/10.3390/nano10050993 - 21 May 2020

Cited by 31 | Viewed by 4396

Abstract

The bifunctional possibilities of Tm,Yb:GdVO₄@SiO₂ core-shell nanoparticles for temperature sensing by using the near-infrared (NIR)-excited upconversion emissions in the first biological window, and biolabeling through the visible emissions they generate, were investigated. The two emission lines located at 700 and [...] Read more.

The bifunctional possibilities of Tm,Yb:GdVO₄@SiO₂ core-shell nanoparticles for temperature sensing by using the near-infrared (NIR)-excited upconversion emissions in the first biological window, and biolabeling through the visible emissions they generate, were investigated. The two emission lines located at 700 and 800 nm, that arise from the thermally coupled ³F_2,3 and ³H₄ energy levels of Tm³⁺, were used to develop a luminescent thermometer, operating through the Fluorescence Intensity Ratio (FIR) technique, with a very high thermal relative sensitivity. Moreover, since the inert shell surrounding the luminescent active core allows for dispersal of the nanoparticles in water and biological compatible fluids, we investigated the penetration depth that can be realized in biological tissues with their emissions in the NIR range, achieving a value of 0.8 mm when excited at powers of 50 mW. After their internalization in HeLa cells, a low toxicity was observed and the potentiality for biolabelling in the visible range was demonstrated, which facilitated the identification of the location of the nanoparticles inside the cells, and the temperature determination. Full article

(This article belongs to the Special Issue Nanosensors)

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17 pages, 4860 KiB

Open AccessArticle

Nickel Nanoparticles Induce the Synthesis of a Tumor-Related Polypeptide in Human Epidermal Keratinocytes

by Javier Jiménez-Lamana, Simon Godin, Gerard Aragonès, Cinta Bladé, Joanna Szpunar and Ryszard Łobinski

Nanomaterials 2020, 10(5), 992; https://doi.org/10.3390/nano10050992 - 21 May 2020

Cited by 8 | Viewed by 3147

Abstract

Although nickel allergy and carcinogenicity are well known, their molecular mechanisms are still uncertain, thus demanding studies at the molecular level. The nickel carcinogenicity is known to be dependent on the chemical form of nickel, since only certain nickel compounds can enter the [...] Read more.

Although nickel allergy and carcinogenicity are well known, their molecular mechanisms are still uncertain, thus demanding studies at the molecular level. The nickel carcinogenicity is known to be dependent on the chemical form of nickel, since only certain nickel compounds can enter the cell. This study investigates, for the first time, the cytotoxicity, cellular uptake, and molecular targets of nickel nanoparticles (NiNPs) in human skin cells in comparison with other chemical forms of nickel. The dose-response curve that was obtained for NiNPs in the cytotoxicity assays showed a linear behavior typical of genotoxic carcinogens. The exposure of keratinocytes to NiNPs leads to the release of Ni²⁺ ions and its accumulation in the cytosol. A 6 kDa nickel-binding molecule was found to be synthesized by cells exposed to NiNPs at a dose corresponding to medium mortality. This molecule was identified to be tumor-related p63-regulated gene 1 protein. Full article

(This article belongs to the Special Issue Advances in Toxicity of Nanoparticles)

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16 pages, 13098 KiB

Open AccessArticle

Engineering Core-Shell Structures of Magnetic Ferrite Nanoparticles for High Hyperthermia Performance

by Mohamed S. A. Darwish, Hohyeon Kim, Hwangjae Lee, Chiseon Ryu, Jae Young Lee and Jungwon Yoon

Nanomaterials 2020, 10(5), 991; https://doi.org/10.3390/nano10050991 - 21 May 2020

Cited by 35 | Viewed by 4583

Abstract

Magnetic ferrite nanoparticles (MFNs) with high heating efficiency are highly desirable for hyperthermia applications. As conventional MFNs usually show low heating efficiency with a lower specific loss power (SLP), extensive efforts to enhance the SLP of MFNs have been made by [...] Read more.

Magnetic ferrite nanoparticles (MFNs) with high heating efficiency are highly desirable for hyperthermia applications. As conventional MFNs usually show low heating efficiency with a lower specific loss power (SLP), extensive efforts to enhance the SLP of MFNs have been made by varying the particle compositions, sizes, and structures. In this study, we attempted to increase the SLP values by creating core-shell structures of MFNs. Accordingly, first we synthesized three different types of core ferrite nanoparticle of magnetite (mag), cobalt ferrite (cf) and zinc cobalt ferrite (zcf). Secondly, we synthesized eight bi-magnetic core-shell structured MFNs; Fe₃O₄@CoFe₂O₄ (mag@cf₁, mag@cf₂), CoFe₂O₄@Fe₃O₄ (cf@mag₁, cf@mag₂), Fe₃O₄@ZnCoFe₂O₄ (mag@zcf₁, mag@zcf₂), and ZnCoFe₂O₄@Fe₃O₄ (zcf@mag₁, zcf@mag₂), using a modified controlled co-precipitation process. SLP values of the prepared core-shell MFNs were investigated with respect to their compositions and core/shell dimensions while varying the applied magnetic field strength. Hyperthermia properties of the prepared core-shell MFNs were further compared to commercial magnetic nanoparticles under the safe limits of magnetic field parameters (<5 × 10⁹ A/(m·s)). As a result, the highest SLP value (379.2 W/g_metal) was obtained for mag@zcf₁, with a magnetic field strength of 50 kA/m and frequency of 97 kHz. On the other hand, the lowest SLP value (1.7 W/g_metal) was obtained for cf@mag₁, with a magnetic field strength of 40 kA/m and frequency of 97 kHz. We also found that magnetic properties and thickness of the shell play critical roles in heating efficiency and hyperthermia performance. In conclusion, we successfully enhanced the SLP of MFNs by engineering their compositions and dimensions. Full article

(This article belongs to the Special Issue Magnetic Nanoparticle-Based Hyperthermia and Theranostics)

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7 pages, 2210 KiB

Open AccessLetter

A New Design of a Thin-Film Thermoelectric Device Based on Multilayer-Structure Module

by Tianbao Chen, Zhuanghao Zheng, Guangxing Liang and Ping Fan

Nanomaterials 2020, 10(5), 990; https://doi.org/10.3390/nano10050990 - 21 May 2020

Cited by 11 | Viewed by 3814

Abstract

In this work, a novel multilayer structure thin-film thermoelectric device is proposed for preparing a high performance generator. The result shows that the output voltage of the three-layer thin-film device has a linear increasing trend with the increasing temperature difference. Additionally, the device [...] Read more.

In this work, a novel multilayer structure thin-film thermoelectric device is proposed for preparing a high performance generator. The result shows that the output voltage of the three-layer thin-film device has a linear increasing trend with the increasing temperature difference. Additionally, the device was also tested as a laser power measurement and displays that it has good sensitivity. Moreover, we also fabricated the multilayer device based on the present three-layer structure. It improves upon the similar output prosperities, confirming that the present multilayer structure thin-film thermoelectric device can be considered for preparing high performance micro-self-powered sources and sensors. Full article

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19 pages, 4747 KiB

Open AccessArticle

Structural Properties of Janus Particles with Nano- and Mesoscale Anisotropy

by Eugen Mircea Anitas

Nanomaterials 2020, 10(5), 989; https://doi.org/10.3390/nano10050989 - 21 May 2020

Cited by 2 | Viewed by 3098

Abstract

Synthesis of anisotropic Janus particles (AnJPs) is crucial for understanding the fundamental principles behind non-equilibrium self-organization of cells, bacteria, or enzymes, and for the design of novel multicomponent carriers for guided self-assembly, drug delivery or molecular imaging. Their catalytic activity, as well as [...] Read more.

Synthesis of anisotropic Janus particles (AnJPs) is crucial for understanding the fundamental principles behind non-equilibrium self-organization of cells, bacteria, or enzymes, and for the design of novel multicomponent carriers for guided self-assembly, drug delivery or molecular imaging. Their catalytic activity, as well as many other chemical and physical properties are intimately related to the nano- and mesoscale structure. An efficient and fast in situ monitoring of the structural changes involves non-destructive techniques which can probe macroscopic volumes of multicomponent systems, such as small-angle scattering (SAS). However, the interpretation of scattering data is often a difficult task since the existing models deal only with symmetric AnJPs, thus greatly restricting their applicability. Here, a general theoretical framework is developed, which describes scattering from a system containing randomly oriented and placed two-phase AnJPs with arbitrarily tunable geometric and chemical asymmetries embedded in a solution/matrix of different chemical composition. This approach allows an analytic description of the contrast matching point, and it is shown that the interplay between the scattering curves of the two phases gives rise to a rich scaling behavior which allows extracting structural information about each individual phase. To illustrate the above findings, analytic expression for the scattering curves of asymmetric AnJPs are derived, and the results are validated by Monte-Carlo simulations. The broad general features of the scattering curves are explained by using a simple scaling approach which allows gaining more physical insight into the scattering processes as well as for the interpretation of SAS intensity. Full article

(This article belongs to the Special Issue Advances in Janus Nanoparticles: Synthesis, Characterization and Applications)

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21 pages, 4563 KiB

Open AccessArticle

(Ag)Pd-Fe₃O₄ Nanocomposites as Novel Catalysts for Methane Partial Oxidation at Low Temperature

by Blanca Martínez-Navarro, Ruth Sanchis, Esther Asedegbega-Nieto, Benjamín Solsona and Francisco Ivars-Barceló

Nanomaterials 2020, 10(5), 988; https://doi.org/10.3390/nano10050988 - 21 May 2020

Cited by 8 | Viewed by 3753

Abstract

Nanostructured composite materials based on noble mono-(Pd) or bi-metallic (Ag/Pd) particles supported on mixed iron oxides (II/III) with bulk magnetite structure (Fe₃O₄) have been developed in order to assess their potential for heterogeneous catalysis applications in methane partial oxidation. [...] Read more.

Nanostructured composite materials based on noble mono-(Pd) or bi-metallic (Ag/Pd) particles supported on mixed iron oxides (II/III) with bulk magnetite structure (Fe₃O₄) have been developed in order to assess their potential for heterogeneous catalysis applications in methane partial oxidation. Advancing the direct transformation of methane into value-added chemicals is consensually accepted as the key to ensuring sustainable development in the forthcoming future. On the one hand, nanosized Fe₃O₄ particles with spherical morphology were synthesized by an aqueous-based reflux method employing different Fe (II)/Fe (III) molar ratios (2 or 4) and reflux temperatures (80, 95 or 110 °C). The solids obtained from a Fe (II)/Fe (III) nominal molar ratio of 4 showed higher specific surface areas which were also found to increase on lowering the reflux temperature. The starting 80 m² g⁻¹ was enhanced up to 140 m² g⁻¹ for the resulting optimized Fe₃O₄-based solid consisting of nanoparticles with a 15 nm average diameter. On the other hand, Pd or Pd-Ag were incorporated post-synthesis, by impregnation on the highest surface Fe₃O₄ nanostructured substrate, using 1–3 wt.% metal load range and maintaining a constant Pd:Ag ratio of 8:2 in the bimetallic sample. The prepared nanocomposite materials were investigated by different physicochemical techniques, such as X-ray diffraction, thermogravimetry (TG) in air or H₂, as well as several compositions and structural aspects using field emission scanning and scanning transmission electron microscopy techniques coupled to energy-dispersive X-ray spectroscopy (EDS). Finally, the catalytic results from a preliminary reactivity study confirmed the potential of magnetite-supported (Ag)Pd catalysts for CH₄ partial oxidation into formaldehyde, with low reaction rates, methane conversion starting at 200 °C, far below temperatures reported in the literature up to now; and very high selectivity to formaldehyde, above 95%, for Fe₃O₄ samples with 3 wt.% metal, either Pd or Pd-Ag. Full article

(This article belongs to the Special Issue Application of New Nanoparticle Structures as Catalysts)

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24 pages, 6116 KiB

Open AccessArticle

Enhanced Photocatalytic Properties of PET Filaments Coated with Ag-N Co-Doped TiO₂ Nanoparticles Sensitized with Disperse Blue Dyes

by Hui Zhang, Qi Tang, Qingshan Li, Qingwen Song, Hailiang Wu and Ningtao Mao

Nanomaterials 2020, 10(5), 987; https://doi.org/10.3390/nano10050987 - 21 May 2020

Cited by 20 | Viewed by 3249

Abstract

In this study, the effects of disperse blue dye-sensitization on the photocatalytic properties of the Ag-N co-doped TiO₂ nanoparticles loaded on polyethylene terephthalate (PET) filaments are investigated under visible light irradiation. The microstructure and photocatalytic properties of the as-synthesized TiO₂ nanocomposites, [...] Read more.

In this study, the effects of disperse blue dye-sensitization on the photocatalytic properties of the Ag-N co-doped TiO₂ nanoparticles loaded on polyethylene terephthalate (PET) filaments are investigated under visible light irradiation. The microstructure and photocatalytic properties of the as-synthesized TiO₂ nanocomposites, as well as the as-prepared PET filaments, are systematically characterized. The photocatalytic performance of the PET filaments coated with the Ag-N co-doped TiO₂ nanoparticles sensitized with disperse blue dyes is evaluated via its capacity of photo-degrading methyl orange (MO) dyes under visible light irradiation. It is found that the holes are the predominant reactive radical species and the hydroxyl and superoxide radicals play a subordinate role in the photocatalytic reaction process. The reaction rate constant of the photocatalytic composite filaments is nearly 4.0 times higher than that of the PET filaments loaded solely with TiO₂ nanoparticles. The resultant photocatalytic composite filaments are evident to be capable of repeatedly photo-degrading MO dyes without losing its photocatalytic activity significantly. Full article

(This article belongs to the Special Issue Nanotechnology in Clothing & Fabrics)

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15 pages, 2665 KiB

Open AccessArticle

Freeze-Dried Softisan^® 649-Based Lipid Nanoparticles for Enhanced Skin Delivery of Cyclosporine A

by Maria Inês Silva, Ana Isabel Barbosa, Sofia A. Costa Lima, Paulo Costa, Tiago Torres and Salette Reis

Nanomaterials 2020, 10(5), 986; https://doi.org/10.3390/nano10050986 - 21 May 2020

Cited by 23 | Viewed by 4322

Abstract

Inflammatory skin diseases, including psoriasis and atopic dermatitis, affect around one quarter to one third of the world population. Systemic cyclosporine A, an immunosuppressant agent, is included in the current therapeutic armamentarium of these diseases. Despite being highly effective, it is associated with [...] Read more.

Inflammatory skin diseases, including psoriasis and atopic dermatitis, affect around one quarter to one third of the world population. Systemic cyclosporine A, an immunosuppressant agent, is included in the current therapeutic armamentarium of these diseases. Despite being highly effective, it is associated with several side effects, and its topical administration is limited by its high molecular weight and poor water solubility. To overcome these limitations, cyclosporine A was incorporated into solid lipid nanoparticles obtained from Softisan^® 649, a commonly used cosmetic ingredient, aiming to develop a vehicle for application to the skin. The nanoparticles presented sizes of around 200 nm, low polydispersity, negative surface charge, and stability when stored for 8 weeks at room temperature or 4 °C. An effective incorporation of 88% of cyclosporine A within the nanoparticles was observed, without affecting its morphology. After the freeze-drying process, the Softisan^® 649-based nanoparticles formed an oleogel. Skin permeation studies using pig ear as a model revealed low permeation of the applied cyclosporine A in the freeze-dried form of the nanoparticles in relation to free drug and the freshly prepared nanoparticles. About 1.0 mg of cyclosporine A was delivered to the skin with reduced transdermal permeation. These results confirm local delivery of cyclosporine A, indicating its promising topical administration. Full article

(This article belongs to the Special Issue Nanocarriers and Targeted Drug Delivery)

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14 pages, 2880 KiB

Open AccessArticle

Three-Dimensional Printed Polylactic Acid (PLA) Surgical Retractors with Sonochemically Immobilized Silver Nanoparticles: The Next Generation of Low-Cost Antimicrobial Surgery Equipment

by Lazaros Tzounis, Petros I. Bangeas, Aristomenis Exadaktylos, Markos Petousis and Nectarios Vidakis

Nanomaterials 2020, 10(5), 985; https://doi.org/10.3390/nano10050985 - 21 May 2020

Cited by 39 | Viewed by 3666

Abstract

A versatile method is reported for the manufacturing of antimicrobial (AM) surgery equipment utilising fused deposition modelling (FDM), three-dimensional (3D) printing and sonochemistry thin-film deposition technology. A surgical retractor was replicated from a commercial polylactic acid (PLA) thermoplastic filament, while a thin layer [...] Read more.

A versatile method is reported for the manufacturing of antimicrobial (AM) surgery equipment utilising fused deposition modelling (FDM), three-dimensional (3D) printing and sonochemistry thin-film deposition technology. A surgical retractor was replicated from a commercial polylactic acid (PLA) thermoplastic filament, while a thin layer of silver (Ag) nanoparticles (NPs) was developed via a simple and scalable sonochemical deposition method. The PLA retractor covered with Ag NPs (PLA@Ag) exhibited vigorous AM properties examined by a reduction in Staphylococcus aureus (S. aureus), Pseudomonas aeruginosa (P. aeruginosa) and Escherichia coli (E. coli) bacteria viability (%) experiments at 30, 60 and 120 min duration of contact (p < 0.05). Scanning electron microscopy (SEM) showed the surface morphology of bare PLA and PLA@Ag retractor, revealing a homogeneous and full surface coverage of Ag NPs. X-Ray diffraction (XRD) analysis indicated the crystallinity of Ag nanocoating. Ultraviolent-visible (UV-vis) spectroscopy and transmission electron microscopy (TEM) highlighted the AgNP plasmonic optical responses and average particle size of 31.08 ± 6.68 nm. TEM images of the PLA@Ag crossection demonstrated the thickness of the deposited Ag nanolayer, as well as an observed tendency of AgNPs to penetrate though the outer surface of PLA. The combination of 3D printing and sonochemistry technology could open new avenues in the manufacturing of low-cost and on-demand antimicrobial surgery equipment. Full article

(This article belongs to the Special Issue Nanoscale Surface Engineering)

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20 pages, 4802 KiB

Open AccessArticle

Detection of Human p53 In-Vitro Expressed in a Transcription-Translation Cell-Free System by a Novel Conjugate Based on Cadmium Sulphide Nanoparticles

by Víctor Barba-Vicente, María Jesús Almendral Parra, Juan Francisco Boyero-Benito, Carlota Auría-Soro, Pablo Juanes-Velasco, Alicia Landeira-Viñuela, Álvaro Furones-Cuadrado, Ángela-Patricia Hernández, Raúl Manzano-Román and Manuel Fuentes

Nanomaterials 2020, 10(5), 984; https://doi.org/10.3390/nano10050984 - 21 May 2020

Cited by 6 | Viewed by 3370

Abstract

Here, cadmium sulphide quantum dots (CdS QDs) have been synthetized and functionalized with Bovine Serum Albumin (BSA) in a colloidal aqueous solution with a stability of over 3 months. Specific synthesis conditions, in homogeneous phase and at low temperature, have allowed limitation of [...] Read more.

Here, cadmium sulphide quantum dots (CdS QDs) have been synthetized and functionalized with Bovine Serum Albumin (BSA) in a colloidal aqueous solution with a stability of over 3 months. Specific synthesis conditions, in homogeneous phase and at low temperature, have allowed limitation of S²⁻ concentration, hence, as a consequence, there is restricted growth of the nanoparticles (NPs). This fact allows binding with BSA in the most favorable manner for the biomolecule. The presence of Cd²⁺ ions on the surface of the CdS nanoparticle is counteracted by the negatively charged domains of the BSA, resulting in the formation of small NPs, with little tendency for aggregation. Temperature and pH have great influence on the fluorescence characteristics of the synthetized nanoparticles. Working at low temperatures (4 °C) and pH 10–11 have proven the best result as shown by hydrolysis kinetic control of the thioacetamide precursor of S²⁻ ion. Biological activity of the coupled BSA is maintained allowing subsequent bioconjugation with other biomolecules such as antibodies. The chemical conjugation with anti-Glutathione S-transferase (α-GST) antibody, a common tag employed in human recombinant fusion proteins, produces a strong quenching of fluorescence that proves the possibilities of its use in biological labelling. Finally, p53, onco-human recombinant protein (GST tagged in COOH terminus), has been in situ IVTT (in vitro transcription-translation) expressed and efficiently captured by the α-GST-CdS QD conjugate as a proof of the biocompatibility on IVTT systems and the functionality of conjugated antibody. Full article

(This article belongs to the Section Biology and Medicines)

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14 pages, 9002 KiB

Open AccessArticle

CeO₂-Supported Pt Catalysts Derived from MOFs by Two Pyrolysis Strategies to Improve the Oxygen Activation Ability

by Xueqing Zhu, Hui He, Yanxia Li, Haoyuan Wu, Mingli Fu, Daiqi Ye, Junliang Wu, Haomin Huang, Yun Hu and Xiaojun Niu

Nanomaterials 2020, 10(5), 983; https://doi.org/10.3390/nano10050983 - 21 May 2020

Cited by 16 | Viewed by 4129

Abstract

Functional metal organic framework (MOF) derivatives have attracted tremendous attention as promising catalysts for various reactions. The thermal decomposition strategies have a vital effect on the structures and physicochemical properties of functional MOF derivatives. Nevertheless, what effect does the pyrolysis strategy have on [...] Read more.

Functional metal organic framework (MOF) derivatives have attracted tremendous attention as promising catalysts for various reactions. The thermal decomposition strategies have a vital effect on the structures and physicochemical properties of functional MOF derivatives. Nevertheless, what effect does the pyrolysis strategy have on MOF derivatives need further study. In this work, one-step (under dry air) and two-step (first under N₂ and then dry air) pyrolysis are chosen to prepare the functional ceria-based MOF derivatives with novel hierarchical pore structure. In comparison with the derivatives prepared by one-step pyrolysis, the two-step pyrolysis composites exhibit better catalytic activity for toluene oxidation due to the higher contents of surface absorbed oxygen species and surface oxygen vacancies. The reusability and durability test demonstrates perfect stability of such functional MOF derivatives. The in-situ UV Raman reveals that two-step strategy is favorable for enhancing the gaseous oxygen activation ability of the functional MOF derivatives. Those findings may instruct the synthesis of functional MOF derivatives via different pyrolysis strategies as well as afford a further understanding of the crucial role of oxygen vacancies. Full article

(This article belongs to the Section Energy and Catalysis)

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18 pages, 4690 KiB

Open AccessReview

Electrospun Nanofibers for Chemical Separation

by Mesbah Najafi and Margaret W. Frey

Nanomaterials 2020, 10(5), 982; https://doi.org/10.3390/nano10050982 - 21 May 2020

Cited by 40 | Viewed by 7566

Abstract

The separation and purification of specific chemicals from a mixture have become necessities for many environments, including agriculture, food science, and pharmaceutical and biomedical industries. Electrospun nanofiber membranes are promising materials for the separation of various species such as particles, biomolecules, dyes, and [...] Read more.

The separation and purification of specific chemicals from a mixture have become necessities for many environments, including agriculture, food science, and pharmaceutical and biomedical industries. Electrospun nanofiber membranes are promising materials for the separation of various species such as particles, biomolecules, dyes, and metals from liquids because of the combined properties of a large specific surface, light weight, high porosity, good connectivity, and tunable wettability. This paper reviews the recent progress in the design and fabrication of electrospun nanofibers for chemical separation. Different capture mechanisms including electrostatic, affinity, covalent bonding, chelation, and magnetic adsorption are explained and their distinct characteristics are highlighted. Finally, the challenges and future aspects of nanofibers for membrane applications are discussed. Full article

(This article belongs to the Special Issue Progress in Electrospun Nanofibers and Nanocomposites)

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12 pages, 1913 KiB

Open AccessArticle

Atomic Layer Deposition of ZnO on Mesoporous Silica: Insights into Growth Behavior of ZnO via In-Situ Thermogravimetric Analysis

by Piyush Ingale, Kristian Knemeyer, Mar Piernavieja Hermida, Raoul Naumann d’Alnoncourt, Arne Thomas and Frank Rosowski

Nanomaterials 2020, 10(5), 981; https://doi.org/10.3390/nano10050981 - 20 May 2020

Cited by 15 | Viewed by 4421

Abstract

ZnO is a remarkable material with many applications in electronics and catalysis. Atomic layer deposition (ALD) of ZnO on flat substrates is an industrially applied and well-known process. Various studies describe the growth of ZnO layers on flat substrates. However, the growth characteristics [...] Read more.

ZnO is a remarkable material with many applications in electronics and catalysis. Atomic layer deposition (ALD) of ZnO on flat substrates is an industrially applied and well-known process. Various studies describe the growth of ZnO layers on flat substrates. However, the growth characteristics and reaction mechanisms of atomic layer deposition of ZnO on mesoporous powders have not been well studied. This study investigates the ZnO ALD process based on diethylzinc (DEZn) and water with silica powder as substrate. In-situ thermogravimetric analysis gives direct access to the growth rates and reaction mechanisms of this process. Ex-situ analytics, e.g., N₂ sorption analysis, XRD, XRF, HRTEM, and STEM-EDX mapping, confirm deposition of homogenous and thin films of ZnO on SiO₂. In summary, this study offers new insights into the fundamentals of an ALD process on high surface area powders. Full article

(This article belongs to the Special Issue ZnO Based Nanostructures: Synthesis, Characterization and Applications)

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