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Nanomaterials, Volume 9, Issue 1 (January 2019)

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Open AccessArticle Linear and Nonlinear Intersubband Optical Properties of Direct Band Gap GeSn Quantum Dots
Nanomaterials 2019, 9(1), 124; https://doi.org/10.3390/nano9010124 (registering DOI)
Received: 2 January 2019 / Revised: 11 January 2019 / Accepted: 15 January 2019 / Published: 19 January 2019
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Abstract
Intersubband optical transitions, refractive index changes, and absorption coefficients are numerically driven for direct bandgap strained GeSn/Ge quantum dots. The linear, third-order nonlinear and total, absorption coefficients and refractive index changes are evaluated over useful dot sizes’ range ensuring p-like Γ-electron energy
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Intersubband optical transitions, refractive index changes, and absorption coefficients are numerically driven for direct bandgap strained GeSn/Ge quantum dots. The linear, third-order nonlinear and total, absorption coefficients and refractive index changes are evaluated over useful dot sizes’ range ensuring p-like Γ-electron energy state to be lower than s-like L-electron energy state. The results show strong dependence of the total absorption coefficient and refractive index changes on the quantum dot sizes. The third order nonlinear contribution is found to be sensitive to the incident light intensity affecting both total absorption coefficient and refractive index changes, especially for larger dot sizes. Full article
(This article belongs to the Special Issue Non-Linear Optical Effects in Nanomaterials)
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Open AccessArticle Titania Nanotubes/Hydroxyapatite Nanocomposites Produced with the Use of the Atomic Layer Deposition Technique: Estimation of Bioactivity and Nanomechanical Properties
Nanomaterials 2019, 9(1), 123; https://doi.org/10.3390/nano9010123 (registering DOI)
Received: 21 December 2018 / Revised: 14 January 2019 / Accepted: 15 January 2019 / Published: 19 January 2019
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Abstract
Titanium dioxide nanotubes/hydroxyapatite nanocomposites were produced on a titanium alloy (Ti6Al4V/TNT/HA) and studied as a biocompatible coating for an implant surface modification. As a novel approach for this type of nanocomposite fabrication, the atomic layer deposition (ALD) method with an extremely low number
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Titanium dioxide nanotubes/hydroxyapatite nanocomposites were produced on a titanium alloy (Ti6Al4V/TNT/HA) and studied as a biocompatible coating for an implant surface modification. As a novel approach for this type of nanocomposite fabrication, the atomic layer deposition (ALD) method with an extremely low number of cycles was used to enrich titania nanotubes (TNT) with a very thin hydroxyapatite coating. X-ray diffraction (XRD) and scanning electron microscopy (SEM) were used for determination of the structure and the surface morphology of the fabricated nanocoatings. The biointegration activity of the layers was estimated based on fibroblasts’ proliferation on the TNT/HA surface. The antibacterial activity was determined by analyzing the ability of the layers to inhibit bacterial colonization and biofilm formation. Mechanical properties of the Ti6Al4V/TNT/HA samples were estimated by measuring the hardness, Young’s module, and susceptibility to scratching. The results revealed that the nanoporous titanium alloy coatings enriched with a very thin hydroxyapatite layer may be a promising way to achieve the desired balance between biofunctional and biomechanical properties of modern implants. Full article
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Open AccessArticle Impaired Liver Size and Compromised Neurobehavioral Activity are Elicited by Chitosan Nanoparticles in the Zebrafish Embryo Model
Nanomaterials 2019, 9(1), 122; https://doi.org/10.3390/nano9010122 (registering DOI)
Received: 21 December 2018 / Revised: 8 January 2019 / Accepted: 15 January 2019 / Published: 19 January 2019
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Abstract
The use of chitosan nanoparticles (ChNPs) in various biological and environmental applications is attracting great interest. However, potential side effects related to ChNP toxicity remain the major limitation hampering their wide application. For the first time, we investigate the potential organ-specific (cardiac, hepatic,
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The use of chitosan nanoparticles (ChNPs) in various biological and environmental applications is attracting great interest. However, potential side effects related to ChNP toxicity remain the major limitation hampering their wide application. For the first time, we investigate the potential organ-specific (cardiac, hepatic, and neuromuscular) toxicity of ChNPs (size 100–150 nm) using the zebrafish embryo model. Our data highlight the absence of both acute and teratogenic toxic effects of ChNPs (~100% survival rate) even at the higher concentration employed (200 mg/L). Although no single sign of cardiotoxicity was observed upon exposure to 200 mg/L of ChNPs, as judged by heartbeat rate, the corrected QT interval (QTc, which measures the time between the start of the Q wave and the end of the T wave in the heart's electrical cycle), maximum cardiac arrest, and ejection fraction assays, the same dosage elicited the impairment of both liver size (decreased liver size, but without steatosis and lipid yolk retention) and neurobehavioral activity (increased movement under different light conditions). Although the observed toxic effect failed to affect embryo survival, whether a prolonged ChNP treatment may induce other potentially harmful effects remains to be elucidated. By reporting new insights on their organ-specific toxicity, our results add novel and useful information into the available data concerning the in vivo effect of ChNPs. Full article
(This article belongs to the Special Issue Biomedical Applications of Nanotechnology)
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Open AccessArticle Enhanced Efficiency of MAPbI3 Perovskite Solar Cells with FAPbX3 Perovskite Quantum Dots
Nanomaterials 2019, 9(1), 121; https://doi.org/10.3390/nano9010121 (registering DOI)
Received: 17 November 2018 / Revised: 20 December 2018 / Accepted: 14 January 2019 / Published: 19 January 2019
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Abstract
We describe a method to enhance power conversion efficiency (PCE) of MAPbI3 perovskite solar cell by inserting a FAPbX3 perovskite quantum dots (QD-FAPbX3) layer. The MAPbI3 and QD-FAPbX3 layers were prepared using a simple, rapid spin-coating method
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We describe a method to enhance power conversion efficiency (PCE) of MAPbI3 perovskite solar cell by inserting a FAPbX3 perovskite quantum dots (QD-FAPbX3) layer. The MAPbI3 and QD-FAPbX3 layers were prepared using a simple, rapid spin-coating method in a nitrogen-filled glove box. The solar cell structure consists of ITO/PEDOT:PSS/MAPbI3/QD-FAPbX3/C60/Ag, where PEDOT:PSS, MAPbI3, QD-FAPbX3, and C60 were used as the hole transport layer, light-absorbing layer, absorption enhance layer, and electron transport layer, respectively. The MAPbI3/QD-FAPbX3 solar cells exhibit a PCE of 7.59%, an open circuit voltage (Voc) of 0.9 V, a short-circuit current density (Jsc) of 17.4 mA/cm2, and a fill factor (FF) of 48.6%, respectively. Full article
(This article belongs to the Special Issue Perovskite Materials and Devices–– Progress and Challenges)
Open AccessArticle Fabrication of Gelatin Methacrylate (GelMA) Scaffolds with Nano- and Micro-Topographical and Morphological Features
Nanomaterials 2019, 9(1), 120; https://doi.org/10.3390/nano9010120 (registering DOI)
Received: 12 December 2018 / Revised: 6 January 2019 / Accepted: 12 January 2019 / Published: 18 January 2019
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Abstract
The design of biomimetic biomaterials for cell culture has become a great tool to study and understand cell behavior, tissue degradation, and lesion. Topographical and morphological features play an important role in modulating cell behavior. In this study, a dual methodology was evaluated
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The design of biomimetic biomaterials for cell culture has become a great tool to study and understand cell behavior, tissue degradation, and lesion. Topographical and morphological features play an important role in modulating cell behavior. In this study, a dual methodology was evaluated to generate novel gelatin methacrylate (GelMA)-based scaffolds with nano and micro topographical and morphological features. First, electrospinning parameters and crosslinking processes were optimized to obtain electrospun nanofibrous scaffolds. GelMA mats were characterized by SEM, FTIR, DSC, TGA, contact angle, and water uptake. Various nanofibrous GelMA mats with defect-free fibers and stability in aqueous media were obtained. Then, micropatterned molds produced by photolithography were used as collectors in the electrospinning process. Thus, biocompatible GelMA nanofibrous scaffolds with micro-patterns that mimic extracellular matrix were obtained successfully by combining two micro/nanofabrication techniques, electrospinning, and micromolding. Taking into account the cell viability results, the methodology used in this study could be considered a valuable tool to develop patterned GelMA based nanofibrous scaffolds for cell culture and tissue engineering. Full article
(This article belongs to the Special Issue Electrospun Nanofibers for Biomedical Applications)
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Open AccessArticle Computational Investigation of Tuning the Electron-Donating Ability in Metal-Free Organic Dyes Featuring an Azobenzene Spacer for Dye-Sensitized Solar Cells
Nanomaterials 2019, 9(1), 119; https://doi.org/10.3390/nano9010119 (registering DOI)
Received: 18 December 2018 / Revised: 9 January 2019 / Accepted: 14 January 2019 / Published: 18 January 2019
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Abstract
A series of donor–π-conjugated spacer–acceptor (D–π–A) organic dyes featuring an azobenzene spacer were designed as chromic dyes and investigated computationally. The electron-donating strength was modified by introducing electron-donating units to the donor side. In particular, the transcis isomerization of the azobenzene-based
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A series of donor–π-conjugated spacer–acceptor (D–π–A) organic dyes featuring an azobenzene spacer were designed as chromic dyes and investigated computationally. The electron-donating strength was modified by introducing electron-donating units to the donor side. In particular, the transcis isomerization of the azobenzene-based dyes and its effect on the optical and electronic properties were further scrutinized. In both trans and cis conformers, a gradual increase in electron-donating strength promoted the natural charge separation between donor and acceptor moieties, thereby allowing the absorption of a longer wavelength of visible light. Importantly, the conformational change of the azobenzene bridge resulted in different absorption spectra and light-harvesting properties. The azobenzene-based dyes will open up a new research path for chromic dye-sensitized solar cells. Full article
(This article belongs to the Special Issue Computational Materials Design for Renewable Energy Applications)
Open AccessArticle Composite Magnetic Photocatalyst Bi5O7I/MnxZn1−xFe2O4: Hydrothermal-Roasting Preparation and Excellent Photocatalytic Activity
Nanomaterials 2019, 9(1), 118; https://doi.org/10.3390/nano9010118 (registering DOI)
Received: 17 December 2018 / Revised: 13 January 2019 / Accepted: 15 January 2019 / Published: 18 January 2019
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Abstract
A new composite magnetic photocatalyst, Bi5O7I/MnxZn1−xFe2O4, prepared by a hydrothermal-roasting method was studied. The photocatalytic properties of Bi5O7I/MnxZn1−xFe2O4 were evaluated
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A new composite magnetic photocatalyst, Bi5O7I/MnxZn1−xFe2O4, prepared by a hydrothermal-roasting method was studied. The photocatalytic properties of Bi5O7I/MnxZn1−xFe2O4 were evaluated by degradation of Rhodamine B (RhB) under simulated sunlight irradiation, and the structures and properties were characterized by X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), transmission electron microscopy (TEM), ultraviolet-visible light (UV-Vis) diffuse reflectance spectra (DRS), and a vibrating sample magnetometer (VSM). The results indicated that Bi5O7I/MnxZn1−xFe2O4 was an orthorhombic crystal, which was similar to that observed for Bi5O7I. Bi5O7I/MnxZn1−xFe2O4 consisted of irregularly shaped nanosheets that were 40–60 nm thick. The most probable pore size was 24.1 nm and the specific surface area was 7.07 m2/g. Bi5O7I/MnxZn1−xFe2O4 could absorb both ultraviolet and visible light, and the energy gap value was 3.22 eV. The saturation magnetization, coercivity and residual magnetization of Bi5O7I/MnxZn1−xFe2O4 were 3.9 emu/g, 126.6 Oe, and 0.7 emu/g respectively, which could help Bi5O7I/MnxZn1−xFe2O4 be separated and recycled from wastewater under the action of an external magnetic field. The recycling experiments revealed that the average recovery rate of the photocatalyst was 90.1%, and the photocatalytic activity was still more than 81.1% after five cycles. Full article
Open AccessArticle ZIF-8-Derived Hollow Carbon for Efficient Adsorption of Antibiotics
Nanomaterials 2019, 9(1), 117; https://doi.org/10.3390/nano9010117 (registering DOI)
Received: 4 December 2018 / Revised: 9 January 2019 / Accepted: 15 January 2019 / Published: 18 January 2019
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Abstract
The harmful nature of high concentrations of antibiotics to humans and animals requires the urgent development of novel materials and techniques for their absorption. In this work, CTAB (Cetyltrimethyl Ammonium Bromide)-assisted synthesis of ZIF-8 (zeolitic imidazolate framework)-derived hollow carbon (ZHC) was designed, prepared,
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The harmful nature of high concentrations of antibiotics to humans and animals requires the urgent development of novel materials and techniques for their absorption. In this work, CTAB (Cetyltrimethyl Ammonium Bromide)-assisted synthesis of ZIF-8 (zeolitic imidazolate framework)-derived hollow carbon (ZHC) was designed, prepared, and used as a high-performance adsorbent, and further evaluated by Langmuir and Freundlich isothermal adsorption experiments, dynamic analysis, as well as theoretical calculation. The maximum capacities of ZHC for adsorbing tetracycline (TC), norfloxacin (NFO), and levofloxacin (OFO) are 267.3, 125.6, and 227.8 mg g-1, respectively, which delivers superior adsorptive performance when compared to widely studied inorganic adsorbates. The design concept of ZIF-8-derived hollow carbon material provides guidance and insights for the efficient adsorbent of environmental antibiotics. Full article
Open AccessArticle Facile Preparation of Self-Assembled Polydopamine-Modified Electrospun Fibers for Highly Effective Removal of Organic Dyes
Nanomaterials 2019, 9(1), 116; https://doi.org/10.3390/nano9010116 (registering DOI)
Received: 4 December 2018 / Revised: 15 January 2019 / Accepted: 16 January 2019 / Published: 18 January 2019
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Abstract
Polydopamine (PDA) nanoparticles can be used as an adsorbent with excellent adsorption capacity. However, nanosized adsorbents are prone to aggregation and thus are severely limited in the field of adsorption. In order to solve this problem, we utilized polydopamine in-situ oxidation self-polymerization on
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Polydopamine (PDA) nanoparticles can be used as an adsorbent with excellent adsorption capacity. However, nanosized adsorbents are prone to aggregation and thus are severely limited in the field of adsorption. In order to solve this problem, we utilized polydopamine in-situ oxidation self-polymerization on the surface of polycaprolactone (PCL)/polyethylene oxide (PEO) electrospun fiber after solvent vapor annealing (SVA) treatment, and successfully designed and prepared a PCL/[email protected] composite membrane. The SVA treatment regulated the microscopic morphology of smooth PCL/PEO electrospun fibers that exhibited a pleated microstructure, increasing the specific surface area, and providing abundant active sites for the anchoring of PDA nanoparticles. The PCL/[email protected] composite obtained by chemical modification of PDA demonstrated numerous active sites for the adsorption of methylene (MB) and methyl orange (MO). In addition, the PCL/[email protected] composites were reusable several times with good reutilization as adsorbents. Therefore, we have developed a highly efficient and non-agglomerated dye adsorbent that exhibits potential large-scale application in dye removal and wastewater purification. Full article
(This article belongs to the Special Issue Application and Behavior of Nanomaterials in Water Treatment)
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Open AccessArticle Facile Electrochemical Sensor for Nanomolar Rutin Detection Based on Magnetite Nanoparticles and Reduced Graphene Oxide Decorated Electrode
Nanomaterials 2019, 9(1), 115; https://doi.org/10.3390/nano9010115 (registering DOI)
Received: 24 December 2018 / Revised: 10 January 2019 / Accepted: 14 January 2019 / Published: 18 January 2019
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Abstract
A new electrochemical sensor for nanomolar rutin detection based on amine-functionalized Fe3O4 nanoparticles and electrochemically reduced graphene oxide nanocomposite modified glassy carbon electrode (NH2-Fe3O4 NPs-ErGO/GCE) was fabricated through a simple method, and the X-ray diffraction
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A new electrochemical sensor for nanomolar rutin detection based on amine-functionalized Fe3O4 nanoparticles and electrochemically reduced graphene oxide nanocomposite modified glassy carbon electrode (NH2-Fe3O4 NPs-ErGO/GCE) was fabricated through a simple method, and the X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), scanning electron microscope (SEM), transmission electron microscope (TEM), vibrating sample magnetometer (VSM) and electrochemical technique were used to characterize the modified electrode. The electrochemical behavior of rutin on the Fe3O4 NPs-ErGO/GCE was studied in detail. The electrochemical response of rutin at this modified electrode was remarkably higher than that of the bare GCE or other modified GCE (GO/GCE, Fe3O4 NPs-GO/GCE, and ErGO/GCE). Under the optimum determination conditions, Fe3O4 NPs-ErGO/GCE provided rutin with a broader detection range of 6.0 nM–0.1 µM; 0.1–8.0 µM and 8.0–80 µM, a minimum detectable concentration of 4.0 nM was obtained after 210 s accumulation. This novel method was applied in determination of rutin in pharmaceutical tablets and urine samples with satisfactory results. Full article
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Open AccessArticle Bio-Preparation and Regulation of Pyrrole Structure Nano-Pigment Based on Biomimetic Membrane
Nanomaterials 2019, 9(1), 114; https://doi.org/10.3390/nano9010114 (registering DOI)
Received: 7 November 2018 / Revised: 4 January 2019 / Accepted: 9 January 2019 / Published: 18 January 2019
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Abstract
Microbial pigments, regarded as the most potential biomass pigments, have lately attracted increasing attention in textile dyeing due to their sustainability and cleaner production. The pyrrole structure microbial pigment, called prodigiosin, recently have become a research hotspot for its bright colors and antibacterial
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Microbial pigments, regarded as the most potential biomass pigments, have lately attracted increasing attention in textile dyeing due to their sustainability and cleaner production. The pyrrole structure microbial pigment, called prodigiosin, recently have become a research hotspot for its bright colors and antibacterial function. However, in most case the extraction and preparation are time-consuming and expensive processes since these kinds of microbial pigments are intracellular metabolites. In order to promote the application of microbial pigments in textile dyeing, a novel idea of preparing dye liquid of pyrrole structure pigments based on fermentation broth was put forward via increasing the proportion of extracellular pigments. A model membrane platform was established with a planar lipid bilayer to investigate transmembrane transport of microbial pigments and permeability barrier of cell membrane. The nano-dispersion of pigments was produced as the dye liquor owing to high-throughput transmembrane transfer of intracellular pigments and the increase of extracellular pigments proportion. The results indicated that the size and surface electrical properties of the pigments had contributed much to the mass transfer. It is also showed that transmembrane transmission of the intracellular pigments could be regulated by physical and chemical methods. With the improvement of transmembrane transfer efficiency of microbial pigments and the proportion of extracellular pigments, the complicated biological separation process could be avoided and the application of microbial pigments in textile dyeing can be promoted. Full article
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Open AccessArticle Effect of Zr Doping on the Magnetic and Phase Transition Properties of VO2 Powder
Nanomaterials 2019, 9(1), 113; https://doi.org/10.3390/nano9010113 (registering DOI)
Received: 12 December 2018 / Revised: 8 January 2019 / Accepted: 13 January 2019 / Published: 18 January 2019
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Abstract
In this work, V1−xZrxO2 powder (x = 0, 0.01, 0.02, 0.04) was synthesized by two step hydrothermal method. The micro-topography, magnetic and phase transition properties have been investigated using various measurement techniques. All prepared V1−xZrx
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In this work, V1−xZrxO2 powder (x = 0, 0.01, 0.02, 0.04) was synthesized by two step hydrothermal method. The micro-topography, magnetic and phase transition properties have been investigated using various measurement techniques. All prepared V1−xZrxO2 powder samples exhibit monoclinic structure at room temperature. With the Zr4+ ions doping concentration increased, the shapes of VO2 particles change from spherical to rectangular slice. Besides, the saturation magnetic moment of the samples decrease with the increase of doped Zr4+ ions concentration, while their phase transition temperature increase gradually with Zr ions doping at a rate of around 2 °C/at% on average. We investigated the Zr doping effects on V-V dimers and confirmed the role of V-V dimers in phase transition. We speculate that more V-V dimers form with Zr doping by magnetic measurements, which result in the monoclinic phase of Zr-doped VO2 sample is more stable than rutile phase. Therefore the phase transition temperature is elevated by Zr doping in our experiment. We further consider that the VO2 phase transition should be ascribed to Peierls transition caused by the changing of V-V dimers. Full article
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Open AccessArticle Bi-Metal Phosphide NiCoP: An Enhanced Catalyst for the Reduction of 4-Nitrophenol
Nanomaterials 2019, 9(1), 112; https://doi.org/10.3390/nano9010112
Received: 26 December 2018 / Accepted: 9 January 2019 / Published: 18 January 2019
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Abstract
Porous phosphide NixCoyP composite nanomaterials are successfully synthesized at different Ni/Co ratios (=0, 0.5, 1, and 2) to reduce 4-nitrophenol. The X-ray diffraction and X-ray photoelectron spectroscopy results demonstrate that the products are CoP, NiCoP/CoP, NiCoP, and NiCoP/Ni2
[...] Read more.
Porous phosphide NixCoyP composite nanomaterials are successfully synthesized at different Ni/Co ratios (=0, 0.5, 1, and 2) to reduce 4-nitrophenol. The X-ray diffraction and X-ray photoelectron spectroscopy results demonstrate that the products are CoP, NiCoP/CoP, NiCoP, and NiCoP/Ni2P when the Ni/Co ratio is 0, 0.5, 1, and 2, respectively. The products exhibit different catalytic performance for reduction of 4-nitrophenol at room temperature. Among them, the pure NiCoP delivers a better catalytic efficiency with k app = 677.4 × 10 2   min 1 and k = 338.7   ( Lg 1 min 1 ) , due to the synergy between Ni and Co atoms. The sequence of catalytic efficiency of different samples is CoP < NiCoP/CoP < NiCoP/Ni2P < NiCoP. Full article
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Open AccessArticle Quantum Dot Doping-Induced Photoluminescence for Facile, Label-Free, and Sensitive Pyrophosphatase Activity Assay and Inhibitor Screening
Nanomaterials 2019, 9(1), 111; https://doi.org/10.3390/nano9010111
Received: 19 December 2018 / Revised: 14 January 2019 / Accepted: 15 January 2019 / Published: 18 January 2019
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Abstract
Development of simple, convenient, and sensitive assay methods for pyrophosphatase (PPase) activity is of importance, for disease diagnosis and drug discovery. Herein, a simple, rapid, label-free, and sensitive fluorescence sensor for PPase activity assay is developed, using Cu2+ doping-induced quantum dot (QD)
[...] Read more.
Development of simple, convenient, and sensitive assay methods for pyrophosphatase (PPase) activity is of importance, for disease diagnosis and drug discovery. Herein, a simple, rapid, label-free, and sensitive fluorescence sensor for PPase activity assay is developed, using Cu2+ doping-induced quantum dot (QD) photoluminescence as a signal reporter. The Cu2+ doping of ZnSe QD can induce a dopant-dependent emission response, which will be inhibited after the premixing of Cu2+ with pyrophosphate (PPi), to form a Cu2+-PPi complex. Then, the hydrolysis of PPi into phosphate (Pi), specifically catalyzed by PPase, liberates the free Cu2+ to regain the QD doping for the fluorescence response, which is highly dependent on the PPase activity. The PPase can be sensitively and selectively assayed, with a detection limit of 0.1 mU/mL. The developed sensing strategy can be also employed for the PPase inhibitor screening. Thus, the current QD doping-based sensing strategy offers an efficient and promising avenue for Cu2+, PPi, or PPase-related target analysis, and might hold great potential for the further applications in the clinical disease diagnosis. Full article
(This article belongs to the Special Issue Applications of Quantum Dots)
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Open AccessArticle Non-Isothermal Crystallisation Kinetics of Carbon Black- Graphene-Based Multimodal-Polyethylene Nanocomposites
Nanomaterials 2019, 9(1), 110; https://doi.org/10.3390/nano9010110
Received: 9 December 2018 / Revised: 9 January 2019 / Accepted: 11 January 2019 / Published: 18 January 2019
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Abstract
The effect of carbon black (CB) and microwave-induced plasma graphene (g) on the crystallisation kinetics of the multimodal high-density polyethylene was studied under non-isothermal conditions. The non-isothermal crystallisation behaviour of the multimodal-high-density polyethylene (HDPE), containing up to 5 wt.% graphene, was compared with
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The effect of carbon black (CB) and microwave-induced plasma graphene (g) on the crystallisation kinetics of the multimodal high-density polyethylene was studied under non-isothermal conditions. The non-isothermal crystallisation behaviour of the multimodal-high-density polyethylene (HDPE), containing up to 5 wt.% graphene, was compared with that of neat multimodal-HDPE and its carbon black based nanocomposites. The results suggested that the non-isothermal crystallisation behaviour of polyethylene (PE)-g nanocomposites relied significantly on both the graphene content and the cooling rate. The addition of graphene caused a change in the mechanism of the nucleation and the crystal growth of the multimodal-HDPE, while carbon black was shown to have little effect. Combined Avrami and Ozawa equations were shown to be effective in describing the non-isothermal crystallisation behaviour of the neat multimodal-HDPE and its nanocomposites. The mean activation energy barrier (ΔE), required for the transportation of the molecular chains from the melt state to the growing crystal surface, gradually diminished as the graphene content increased, which is attributable to the nucleating agent effect of graphene platelets. On the contrary, the synergistic effect resulting from the PE-CB nanocomposite decreased the ΔE of the neat multimodal-HDPE significantly at the lowest carbon black content. Full article
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Open AccessArticle Atomistic Study of Mechanical Behaviors of Carbon Honeycombs
Nanomaterials 2019, 9(1), 109; https://doi.org/10.3390/nano9010109
Received: 11 December 2018 / Revised: 3 January 2019 / Accepted: 14 January 2019 / Published: 18 January 2019
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Abstract
With an ultralarge surface-to-volume ratio, a recently synthesized three-dimensional graphene structure, namely, carbon honeycomb, promises important engineering applications. Herein, we have investigated, via molecular dynamics simulations, its mechanical properties, which are inevitable for its integrity and desirable for any feasible implementations. The uniaxial
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With an ultralarge surface-to-volume ratio, a recently synthesized three-dimensional graphene structure, namely, carbon honeycomb, promises important engineering applications. Herein, we have investigated, via molecular dynamics simulations, its mechanical properties, which are inevitable for its integrity and desirable for any feasible implementations. The uniaxial tension and nanoindentation behaviors are numerically examined. Stress–strain curves manifest a transformation of covalent bonds of hinge atoms when they are stretched in the channel direction. The load–displacement curve in nanoindentation simulation implies the hardness and Young’s modulus to be 50.9 GPa and 461±9 GPa, respectively. Our results might be useful for material and device design for carbon honeycomb-based systems. Full article
(This article belongs to the Special Issue Electronic and Thermal Properties of Graphene)
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Open AccessEditorial Acknowledgement to Reviewers of Nanomaterials in 2018
Nanomaterials 2019, 9(1), 108; https://doi.org/10.3390/nano9010108
Published: 17 January 2019
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Abstract
Rigorous peer-review is the corner-stone of high-quality academic publishing [...] Full article
Open AccessArticle Manufacture of Highly Transparent and Hazy Cellulose Nanofibril Films via Coating TEMPO-Oxidized Wood Fibers
Nanomaterials 2019, 9(1), 107; https://doi.org/10.3390/nano9010107
Received: 16 November 2018 / Revised: 25 December 2018 / Accepted: 9 January 2019 / Published: 16 January 2019
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Abstract
Traditionally, inorganic nanoparticles (SiO2, TiO2) have been utilized to tune the optical haze of optoelectronic devices. However, restricted to complex and costly processes for incorporating these nanoparticles, a simple and low-cost approach becomes particularly important. In this work, a
[...] Read more.
Traditionally, inorganic nanoparticles (SiO2, TiO2) have been utilized to tune the optical haze of optoelectronic devices. However, restricted to complex and costly processes for incorporating these nanoparticles, a simple and low-cost approach becomes particularly important. In this work, a simple, effective, and low-cost method was proposed to improve optical haze of transparent cellulose nanofibril films by directly depositing micro-sized 2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPO)-oxidized wood fibers (“coating” method). The obtained films had a high total transmittance of 85% and a high haze of 62%. The film samples also showed a high tensile strength of 80 MPa and excellent thermal stability. Dual sides of the obtained films had different microstructures: one side was extremely smooth (root-mean-square roughness of 6.25 nm), and the other was extremely rough (root-mean-square roughness of 918 nm). As a reference, micro-sized TEMPO-oxidized wood fibers and cellulose nanofibrils were mixed to form a transparent and hazy film (“blending” method). These results show that hazy transparent films prepared using the “coating” method exhibit superior application performances than films prepared using the “blending” method. Full article
(This article belongs to the Special Issue Cellulose Nanomaterials)
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Open AccessArticle Lignin-Based Carbon Nanofibers as Electrodes for Vanadium Redox Couple Electrochemistry
Nanomaterials 2019, 9(1), 106; https://doi.org/10.3390/nano9010106
Received: 30 November 2018 / Revised: 19 December 2018 / Accepted: 11 January 2019 / Published: 16 January 2019
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Abstract
Three different types of lignin (kraft, organosolv and phosphoric acid lignin) were characterized and tested as precursors of electrospun nanofibers. Polyethylene oxide (PEO) was added as a plasticizer and dimethyl formamide (DMF) employed as a solvent. It was found that the molecular weight
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Three different types of lignin (kraft, organosolv and phosphoric acid lignin) were characterized and tested as precursors of electrospun nanofibers. Polyethylene oxide (PEO) was added as a plasticizer and dimethyl formamide (DMF) employed as a solvent. It was found that the molecular weight of lignin was the key parameter to understand the differences of the mechanical stability of the resultant fiber mats. In the case of kraft lignin (KL), the influence of some changes in the synthetic process was also tested: applied voltage, pretreatment in air or not, and the addition of a small amount of Ketjen black. After pyrolysis in nitrogen flow, the obtained carbon nanofibers (CNFs) were characterized by different techniques to analyze their differences in morphology and surface chemistry. Vanadium electrochemistry in 3M sulfuric acid was used to evaluate the different CNFs. All fibers allowed electrochemical reactions, but we observed that the oxidation of V(II) to V(III) was very sensitive to the nature of the raw material. Materials prepared from kraft and phosphorus lignin showed the best performances. Nevertheless, when 1 wt.% of Ketjen black was added to KL during the electrospinning, the electrochemical performance of the sample was significantly improved and all targeted reactions for an all-vanadium redox flow battery were observed. Therefore, in this work, we demonstrated that CNFs obtained by the electrospinning of lignin can be employed as electrodes for vanadium electrochemistry, and their properties can be tuned to improve their electrochemical properties. Full article
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Open AccessReview Vectors for Glioblastoma Gene Therapy: Viral & Non-Viral Delivery Strategies
Nanomaterials 2019, 9(1), 105; https://doi.org/10.3390/nano9010105
Received: 13 November 2018 / Revised: 21 December 2018 / Accepted: 3 January 2019 / Published: 16 January 2019
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Abstract
Glioblastoma multiforme is the most common and aggressive primary brain tumor. Even with aggressive treatment including surgical resection, radiation, and chemotherapy, patient outcomes remain poor, with five-year survival rates at only 10%. Barriers to treatment include inefficient drug delivery across the blood brain
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Glioblastoma multiforme is the most common and aggressive primary brain tumor. Even with aggressive treatment including surgical resection, radiation, and chemotherapy, patient outcomes remain poor, with five-year survival rates at only 10%. Barriers to treatment include inefficient drug delivery across the blood brain barrier and development of drug resistance. Because gliomas occur due to sequential acquisition of genetic alterations, gene therapy represents a promising alternative to overcome limitations of conventional therapy. Gene or nucleic acid carriers must be used to deliver these therapies successfully into tumor tissue and have been extensively studied. Viral vectors have been evaluated in clinical trials for glioblastoma gene therapy but have not achieved FDA approval due to issues with viral delivery, inefficient tumor penetration, and limited efficacy. Non-viral vectors have been explored for delivery of glioma gene therapy and have shown promise as gene vectors for glioma treatment in preclinical studies and a few non-polymeric vectors have entered clinical trials. In this review, delivery systems including viral, non-polymeric, and polymeric vectors that have been used in glioblastoma multiforme (GBM) gene therapy are discussed. Additionally, advances in glioblastoma gene therapy using viral and non-polymeric vectors in clinical trials and emerging polymeric vectors for glioma gene therapy are discussed. Full article
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Open AccessArticle Turn-On Fluorescence Aptasensor on Magnetic Nanobeads for Aflatoxin M1 Detection Based on an Exonuclease III-Assisted Signal Amplification Strategy
Nanomaterials 2019, 9(1), 104; https://doi.org/10.3390/nano9010104
Received: 18 December 2018 / Revised: 9 January 2019 / Accepted: 10 January 2019 / Published: 16 January 2019
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Abstract
In order to satisfy the need for sensitive detection of Aflatoxin M1 (AFM1), we constructed a simple and signal-on fluorescence aptasensor based on an autocatalytic Exonuclease III (Exo III)-assisted signal amplification strategy. In this sensor, the DNA hybridization on magnetic nanobeads could be
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In order to satisfy the need for sensitive detection of Aflatoxin M1 (AFM1), we constructed a simple and signal-on fluorescence aptasensor based on an autocatalytic Exonuclease III (Exo III)-assisted signal amplification strategy. In this sensor, the DNA hybridization on magnetic nanobeads could be triggered by the target AFM1, resulting in the release of a single-stranded DNA to induce an Exo III-assisted signal amplification, in which numerous G-quadruplex structures would be produced and then associated with the fluorescent dye to generate significantly amplified fluorescence signals resulting in the increased sensitivity. Under the optimized conditions, this aptasensor was able to detect AFM1 with a practical detection limit of 9.73 ng kg−1 in milk samples. Furthermore, the prepared sensor was successfully used for detection of AFM1 in the commercially available milk samples with the recovery percentages ranging from 80.13% to 108.67%. Also, the sensor performance was evaluated by the commercial immunoassay kit with satisfactory results. Full article
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Open AccessReview Sustainable Porous Carbon Materials Derived from Wood-Based Biopolymers for CO2 Capture
Nanomaterials 2019, 9(1), 103; https://doi.org/10.3390/nano9010103
Received: 26 December 2018 / Revised: 10 January 2019 / Accepted: 11 January 2019 / Published: 16 January 2019
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Abstract
Porous carbon materials with tunable porosities and functionalities represent an important class of CO2 sorbents. The development of porous carbons from various types of biomass is a sustainable, economic and environmentally friendly strategy. Wood is a biodegradable, renewable, sustainable, naturally abundant and
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Porous carbon materials with tunable porosities and functionalities represent an important class of CO2 sorbents. The development of porous carbons from various types of biomass is a sustainable, economic and environmentally friendly strategy. Wood is a biodegradable, renewable, sustainable, naturally abundant and carbon-rich raw material. Given these advantages, the use of wood-based resources for the synthesis of functional porous carbons has attracted great interests. In this mini-review, we present the recent developments regarding sustainable porous carbons derived from wood-based biopolymers (cellulose, hemicelluloses and lignin) and their application in CO2 capture. Full article
(This article belongs to the Special Issue Nanomaterials in CO2 Capture)
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Open AccessArticle Notable Enhancement of Phase Transition Performance and Luminous Transmittance in VO2 Films via Simple Method of Ar/O Plasma Post-Treatment
Nanomaterials 2019, 9(1), 102; https://doi.org/10.3390/nano9010102
Received: 16 December 2018 / Revised: 9 January 2019 / Accepted: 10 January 2019 / Published: 16 January 2019
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Abstract
Ar/O plasma irradiation is proposed for post-treatment of vanadium dioxide (VO2) films. Oxidation and surface migration were observed in the VO2 films following irradiation. This combined effect leads to an effective stoichiometry refinement and microstructure reconstruction in the interfacial area.
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Ar/O plasma irradiation is proposed for post-treatment of vanadium dioxide (VO2) films. Oxidation and surface migration were observed in the VO2 films following irradiation. This combined effect leads to an effective stoichiometry refinement and microstructure reconstruction in the interfacial area. A notable improvement in luminous transmittance and an enhancement in phase transition performance of the treated VO2 films were achieved. Compared with that of as-deposited VO2 films, the electrical phase transition amplitude of treated films increased more than two-fold. The relative improvement in luminous transmittance (380–780 nm) is 47.4% (from 25.1% to 37%) and the increase in solar transmittance is 66.9% (from 29.9% to 49.9%), which is comparable to or better than the previous work using anti-reflection (AR) coatings or doping methods. The interfacial boundary state proved to be crucial and Ar/O plasma irradiation offers an effective approach for further refinement of thermochromic VO2 films. Full article
(This article belongs to the Special Issue Design and Development of Nanostructured Thin Films)
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Open AccessArticle Polystyrene as Graphene Film and 3D Graphene Sponge Precursor
Nanomaterials 2019, 9(1), 101; https://doi.org/10.3390/nano9010101
Received: 21 December 2018 / Accepted: 10 January 2019 / Published: 16 January 2019
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Abstract
Polystyrene as a thin film on arbitrary substrates or pellets form defective graphene/graphitic films or powders that can be dispersed in water and organic solvents. The materials were characterized by visible absorption, Raman and X-ray photoelectron spectroscopy, electron and atomic force microscopy, and
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Polystyrene as a thin film on arbitrary substrates or pellets form defective graphene/graphitic films or powders that can be dispersed in water and organic solvents. The materials were characterized by visible absorption, Raman and X-ray photoelectron spectroscopy, electron and atomic force microscopy, and electrochemistry. Raman spectra of these materials showed the presence of the expected 2D, G, and D peaks at 2750, 1590, and 1350 cm−1, respectively. The relative intensity of the G versus the D peak was taken as a quantitative indicator of the density of defects in the G layer. Full article
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Open AccessArticle Mechanochemically Synthesised Coal-Based Magnetic Carbon Composites for Removing As(V) and Cd(II) from Aqueous Solutions
Nanomaterials 2019, 9(1), 100; https://doi.org/10.3390/nano9010100
Received: 4 December 2018 / Revised: 11 January 2019 / Accepted: 13 January 2019 / Published: 16 January 2019
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Abstract
The continued decrease in water quality requires new advances in the treatment of wastewater, including the preparation of novel, effective, environmentally friendly, and affordable sorbents of toxic pollutants. We introduce a simple non-conventional mechanochemical synthesis of magnetically responsive materials. Magnetic lignite and magnetic
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The continued decrease in water quality requires new advances in the treatment of wastewater, including the preparation of novel, effective, environmentally friendly, and affordable sorbents of toxic pollutants. We introduce a simple non-conventional mechanochemical synthesis of magnetically responsive materials. Magnetic lignite and magnetic char were prepared by high-energy ball co-milling from either raw Slovak lignite or coal-based char together with a ferrofluid. The products were characterised by X-ray diffraction, electron microscopy, 57Fe Mössbauer spectroscopy, X-ray photoelectron spectroscopy (XPS), volumetric magnetic susceptibility, and low-temperature nitrogen adsorption, and both magnetic carbons were comparatively tested as potential sorbents of As(V) oxyanions and Cd(II) cations in aqueous solutions. The magnetic char was an excellent sorbent of As(V) oxyanions (Qm = 19.9 mg/g at pH 3.9), whereas the magnetic lignite was less effective. The different sorption properties towards arsenic anions may have been due to different oxidation states of iron on the surfaces of the two magnetic composites (determined by XPS), although the overall state of iron monitored by Mössbauer spectroscopy was similar for both samples. Both magnetic composites were effective sorbents for removing Cd(II) cations (Qm (magnetic lignite) = 70.4 mg/g at pH 6.5; Qm (magnetic char) = 58.8 mg/g at pH 6.8). Full article
(This article belongs to the Special Issue Ferromagnetic and Magnetic Properties of Nanostructures)
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Open AccessArticle Intrinsic Defect Engineering in Eu3+ Doped ZnWO4 for Annealing Temperature Tunable Photoluminescence
Nanomaterials 2019, 9(1), 99; https://doi.org/10.3390/nano9010099
Received: 5 December 2018 / Revised: 9 January 2019 / Accepted: 10 January 2019 / Published: 15 January 2019
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Abstract
Eu3+ doped ZnWO4 phosphors were synthesized via the co-precipitation technique followed by subsequent thermal annealing in the range of 400–1000 °C. The phase, morphology, elemental composition, chemical states, optical absorption, and photoluminescence (PL) of the phosphors were characterized by X-ray diffraction,
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Eu3+ doped ZnWO4 phosphors were synthesized via the co-precipitation technique followed by subsequent thermal annealing in the range of 400–1000 °C. The phase, morphology, elemental composition, chemical states, optical absorption, and photoluminescence (PL) of the phosphors were characterized by X-ray diffraction, scanning electron microscopy, dispersive X-ray spectroscopy, X-ray photoelectron spectrometry, diffuse UV–vis reflectance spectroscopy, PL spectrophotometry, and PL lifetime spectroscopy, respectively. It is found that the PL from Eu3+ doped ZnWO4 is tunable through the control of the annealing temperature. Density functional calculations and optical absorption confirm that thermal annealing created intrinsic defects in ZnWO4 lattices play a pivotal role in the color tunable emissions of the Eu3+ doped ZnWO4 phosphors. These data have demonstrated that intrinsic defect engineering in ZnWO4 lattice is an alternative and effective strategy for tuning the emission color of Eu3+ doped ZnWO4. This work shows how to harness the intrinsic defects in ZnWO4 for the preparation of color tunable light-emitting phosphors. Full article
(This article belongs to the Special Issue Luminescent Rare-Earth Based Nanomaterials)
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Open AccessReview Plasma and Nanomaterials: Fabrication and Biomedical Applications
Nanomaterials 2019, 9(1), 98; https://doi.org/10.3390/nano9010098
Received: 17 December 2018 / Revised: 28 December 2018 / Accepted: 8 January 2019 / Published: 14 January 2019
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Abstract
Application of plasma medicine has been actively explored during last several years. Treating every type of cancer remains a difficult task for medical personnel due to the wide variety of cancer cell selectivity. Research in advanced plasma physics has led to the development
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Application of plasma medicine has been actively explored during last several years. Treating every type of cancer remains a difficult task for medical personnel due to the wide variety of cancer cell selectivity. Research in advanced plasma physics has led to the development of different types of non-thermal plasma devices, such as plasma jets, and dielectric barrier discharges. Non-thermal plasma generates many charged particles and reactive species when brought into contact with biological samples. The main constituents include reactive nitrogen species, reactive oxygen species, and plasma ultra-violets. These species can be applied to synthesize biologically important nanomaterials or can be used with nanomaterials for various kinds of biomedical applications to improve human health. This review reports recent updates on plasma-based synthesis of biologically important nanomaterials and synergy of plasma with nanomaterials for various kind of biological applications. Full article
(This article belongs to the Special Issue Biomedical Applications of Nanoparticles)
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Open AccessReview Magnetic-Plasmonic Heterodimer Nanoparticles: Designing Contemporarily Features for Emerging Biomedical Diagnosis and Treatments
Nanomaterials 2019, 9(1), 97; https://doi.org/10.3390/nano9010097
Received: 12 December 2018 / Revised: 4 January 2019 / Accepted: 8 January 2019 / Published: 13 January 2019
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Abstract
Magnetic-plasmonic heterodimer nanostructures synergistically present excellent magnetic and plasmonic characteristics in a unique platform as a multipurpose medium for recently invented biomedical applications, such as magnetic hyperthermia, photothermal therapy, drug delivery, bioimaging, and biosensing. In this review, we briefly outline the less-known aspects
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Magnetic-plasmonic heterodimer nanostructures synergistically present excellent magnetic and plasmonic characteristics in a unique platform as a multipurpose medium for recently invented biomedical applications, such as magnetic hyperthermia, photothermal therapy, drug delivery, bioimaging, and biosensing. In this review, we briefly outline the less-known aspects of heterodimers, including electronic composition, interfacial morphology, critical properties, and present concrete examples of recent progress in synthesis and applications. With a focus on emerging features and performance of heterodimers in biomedical applications, this review provides a comprehensive perspective of novel achievements and suggests a fruitful framework for future research. Full article
(This article belongs to the Special Issue Ferromagnetic and Magnetic Properties of Nanostructures)
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Open AccessReview Neurotoxicity of Nanomaterials: An Up-to-Date Overview
Nanomaterials 2019, 9(1), 96; https://doi.org/10.3390/nano9010096
Received: 10 December 2018 / Revised: 22 December 2018 / Accepted: 8 January 2019 / Published: 13 January 2019
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Abstract
The field of nanotechnology, through which nanomaterials are designed, characterized, produced, and applied, is rapidly emerging in various fields, including energy, electronics, food and agriculture, environmental science, cosmetics, and medicine. The most common biomedical applications of nanomaterials involve drug delivery, bioimaging, and gene
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The field of nanotechnology, through which nanomaterials are designed, characterized, produced, and applied, is rapidly emerging in various fields, including energy, electronics, food and agriculture, environmental science, cosmetics, and medicine. The most common biomedical applications of nanomaterials involve drug delivery, bioimaging, and gene and cancer therapy. Since they possess unique properties which are different than bulk materials, toxic effects and long-term impacts on organisms are not completely known. Therefore, the purpose of this review is to emphasize the main neurotoxic effects induced by nanoparticles, liposomes, dendrimers, carbon nanotubes, and quantum dots, as well as the key neurotoxicology assays to evaluate them. Full article
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Open AccessArticle Improving of the Photovoltaic Characteristics of Dye-Sensitized Solar Cells Using a Photoelectrode with Electrospun Porous TiO2 Nanofibers
Nanomaterials 2019, 9(1), 95; https://doi.org/10.3390/nano9010095
Received: 11 December 2018 / Revised: 5 January 2019 / Accepted: 8 January 2019 / Published: 12 January 2019
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Abstract
Porous TiO2 nanofibers (PTFs) and dense TiO2 nanofibers (DTFs) were prepared using simple electrospinning for application in dye-sensitized solar cells (DSSCs). TiO2 nanoparticles (TNPs) were prepared using a hydrothermal reaction. The as-prepared PTFs and DTFs (with a fiber diameter of
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Porous TiO2 nanofibers (PTFs) and dense TiO2 nanofibers (DTFs) were prepared using simple electrospinning for application in dye-sensitized solar cells (DSSCs). TiO2 nanoparticles (TNPs) were prepared using a hydrothermal reaction. The as-prepared PTFs and DTFs (with a fiber diameter of around 200 nm) were mixed with TNPs such as TNP-PTF and TNP-DTF nanocomposites used in photoelectrode materials or were coated as light scattering layers on the photoelectrodes to improve the charge transfer ability and light harvesting effect of the DSSCs. The as-prepared TNPs showed a pure anatase phase, while the PTFs and DTFs showed both the anatase and rutile phases. The TNP-PTF composite (TNP:PTF = 9:1 wt.%) exhibited an enhanced short circuit photocurrent density (Jsc) of 14.95 ± 1.03 mA cm−2 and a photoelectric conversion efficiency (PCE, η) of 5.4 ± 0.17% because of the improved charge transport and accessibility for the electrolyte ions. In addition, the TNP/PTF photoelectrode showed excellent light absorption in the visible region because of the mountainous nature of light induced by the PTF light scattering layer. The TNP/PTF photoelectrode showed the highest Jsc (16.96 ± 0.79 mA cm−2), η (5.9 ± 0.13%), and open circuit voltage (Voc, 0.66 ± 0.02 V). Full article
(This article belongs to the Special Issue Soft, Biological and Composite Nanomaterials)
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