Subscribe: Journal of Nanomaterials
http://www.hindawi.com/journals/jnm/rss.xml
Preview: Journal of Nanomaterials

Journal of Nanomaterials



The latest articles from Hindawi



Copyright: © 2018 , Hindawi Limited . All rights reserved.
 



Integration of Porous Carbon Nanowrinkles into Carbon Micropost Array for Microsupercapacitors

Mon, 22 Jan 2018 00:00:00 +0000

Porous carbon nanowrinkles (PCW) coated on carbon micropost (CMP) arrays were successfully fabricated via three-step process, which took advantages of the large difference in elastic moduli between PCW and the raw material of CMP. The effect of nanowrinkle integration on the electrochemical performances was investigated, showing an improved electrochemical performance. The electrode also shows excellent cycling stability, which retains 84% of its initial discharge capacitance after 1700 cycles with >90% Coulombic efficiency. This enhanced electrochemical performance is ascribed to the synergistic effect of enlarged surface area and porous structure of PCW. The obtained PCW/CMP compositing electrode with the advantages of low cost and easy scaling-up has great potential for on-chip supercapacitors.



Morphology Evolution of Mn-Si Composition Gradient Micro/Nanomaterials Prepared by Oxygen Assisted Chemical Vapor Deposition

Thu, 18 Jan 2018 07:11:43 +0000

The micro/nanostructure of manganese silicide (Mn-Si) compounds with various morphologies (nanowires, films, particles, and polyhedron shape structure) has been synthesized through oxygen assisted chemical vapor deposition by changing the stacking geometry of manganese powder. Polyhedrons prepared in the Mn-Si contact area were identified to be chemical composition gradient functionally graded materials which were verified by analyzing atomic ratio of Mn/Si from top to bottom. Evolution of morphology greatly depended on the stacking shape correlated distance from precursor to the substrate, resulting in distinctive growth mechanisms. Main structures on the substrate have been verified to be Mn5Si3 and Mn4Si7 with different Mn stacking in bumps comparing to sole Mn4Si7 with flat surface.



On the Stress Transfer of Nanoscale Interlayer with Surface Effects

Wed, 17 Jan 2018 08:48:03 +0000

An improved shear-lag model is proposed to investigate the mechanism through which the surface effect influences the stress transfer of multilayered structures. The surface effect of the interlayer is characterized in terms of interfacial stress and surface elasticity by using Gurtin–Murdoch elasticity theory. Our calculation result shows that the surface effect influences the efficiency of stress transfer. The surface effect is enhanced with decreasing interlayer thickness and elastic modulus. Nonuniform and large residual surface stress distribution amplifies the influence of the surface effect on stress concentration.



Embedding of Bacterial Cellulose Nanofibers within PHEMA Hydrogel Matrices: Tunable Stiffness Composites with Potential for Biomedical Applications

Wed, 17 Jan 2018 07:26:57 +0000

Bacterial cellulose (BC) and poly(2-hydroxyethyl methacrylate) (PHEMA) hydrogels are both considered as biocompatible materials with potential use in various biomedical applications including cartilage, cardiovascular stent, and soft tissue engineering. In this work, the “ever-wet” process based on in situ UV radical polymerization of HEMA monomer in BC nanofibrous structure impregnated with HEMA was used, and a series of BC-PHEMA composites was prepared. The composite structures were characterized by ATR FT-IR spectroscopy, WAXD, SEM, and TEM techniques. The strategy of using densified BC material of various cellulose fiber contents was applied to improve mechanical properties. The mechanical properties were tested under tensile, dynamic shear, and relaxation modes. The final composites contained 1 to 20 wt% of BC; the effect of the reinforcement degree on morphology, swelling capacity, and mechanical properties was investigated. The biocompatibility test of BC-PHEMA composites was performed using mouse mesenchymal stem cells.



Perovskite-Based Solar Cells: Materials, Methods, and Future Perspectives

Mon, 15 Jan 2018 10:07:43 +0000

A novel all-solid-state, hybrid solar cell based on organic-inorganic metal halide perovskite (CH3NH3PbX3) materials has attracted great attention from the researchers all over the world and is considered to be one of the top 10 scientific breakthroughs in 2013. The perovskite materials can be used not only as light-absorbing layer, but also as an electron/hole transport layer due to the advantages of its high extinction coefficient, high charge mobility, long carrier lifetime, and long carrier diffusion distance. The photoelectric power conversion efficiency of the perovskite solar cells has increased from 3.8% in 2009 to 22.1% in 2016, making perovskite solar cells the best potential candidate for the new generation of solar cells to replace traditional silicon solar cells in the future. In this paper, we introduce the development and mechanism of perovskite solar cells, describe the specific function of each layer, and focus on the improvement in the function of such layers and its influence on the cell performance. Next, the synthesis methods of the perovskite light-absorbing layer and the performance characteristics are discussed. Finally, the challenges and prospects for the development of perovskite solar cells are also briefly presented.



Design and Construction of Capacitors with the Use of Nano-Barium Titanate’s (BaTiO3) Composite Materials

Mon, 15 Jan 2018 09:12:09 +0000

The basic idea of this work, from the beginning of the laboratory work till now, is to develop innovative polymer composite materials using nanoparticles that can polarize in such a way that electrical energy can be stored. A number of thermosetting polymers have been laboratory-polymerized and then mixed with barium titanate nanoparticles, in order to develop new polymer nanocomposites. Barium titanate is a well-known dielectric material, which is used in sensors and actuators as it is a piezoelectric and ferroelectric material. In this work, we examine the storage capability between different types of such composites by creating passive filters.



Influence of Milling Time on Structural and Microstructural Parameters of Ni50Ti50 Prepared by Mechanical Alloying Using Rietveld Analysis

Sun, 14 Jan 2018 10:13:49 +0000

Nanostructured Ni50Ti50 powders were prepared by mechanical alloying from elemental Ni and Ti micrometer-sized powders, using a planetary ball mill type Fritsch Pulverisette 7. In this study, the effect of milling time on the evolution of structural and microstructural parameters is investigated. Through Rietveld refinements of X-ray diffraction patterns, phase composition and structural/microstructural parameters such as lattice parameters, average crystallite size , microstrain , and stacking faults probability (SFP) in the frame of MAUD software have been obtained. For prolonged milling time, a mixture of amorphous phase, NiTi-martensite (B19′), and NiTi-austenite (B2) phases, in addition to FCC-Ni(Ti) and HCP-Ti(Ni) solid solutions, is formed. The crystallite size decreases to the nanometer scale while the internal strain increases. It is observed that, for longer milling time, plastic deformations introduce a large amount of stacking faults in HCP-Ti(Ni) rather than in FCC-Ni(Ti), which are mainly responsible for the observed large amount of the amorphous phase.



Heparin-Based Nanoparticles: An Overview of Their Applications

Sun, 14 Jan 2018 07:31:08 +0000

This review deals with nanoparticles synthesized using heparin. Such nanoparticles have been widely studied since a long time ago, obtaining satisfactory outcomes. An outstanding aspect of these nanoparticles is that they possess good biocompatible characteristics, and since heparin is produced in the human body within the mast cells, this makes these nanoparticles useful for future applications like imaging, disease and cancer treatment, and antibacterial activity. They can also be used for applications that are not oriented directly to the medical and biological areas such as in the case of analyte detection in aqueous solution, although such studies are very few. These nanoparticles synthesis is mainly through wet chemistry methods, using heparin that could have been modified or not.



Dynamic Infrared Thermography of Nanoheaters Embedded in Skin-Equivalent Phantoms

Sun, 14 Jan 2018 00:00:00 +0000

Nanoheaters are promising tools for localized photothermal therapy (PTT) of malignant cells. The anisotropic AuNPs present tunable surface plasmon resonances (SPR) with ideal NIR optical response to be applied as theranostic agents. To this purpose, nanoparticles with branches are suitable because of the electromagnetic field concentrated at their vertices. We standardized a protocol to synthesize multibranched gold nanoparticles (MB-AuNPs) by the seed-growth method and found a size-seed dependence tunability on the hierarchy of branching. Once the optical response is evaluated, we tested the temporal stability as nanoheaters of the MB-AuNPs immersed in skin-equivalent phantoms by dynamic infrared thermography (DIRT). The most suited sample presents a concentration of  MB-AuNPs/mL showing good thermal stability with = 4.5°C, during 3 cycles of 10 min at 785 nm laser irradiation with power of 0.15 W. According to these results, the MB-AuNPs are suitable nanoheaters to be tested for PTT in more complex models.



Electrical Breakdown Properties of Clay-Based LDPE Blends and Nanocomposites

Thu, 11 Jan 2018 07:10:53 +0000

Microstructure and electrical breakdown properties of blends and nanocomposites based on low-density polyethylene (LDPE) have been discussed. A series of LDPE nanocomposites containing different amount of organomodified montmorillonite (clay) with and without compatibilizer have been prepared by means of melt compounding. Two sets of blends of LDPE with two grades of Styrene-Ethylene-Butylene-Styrene block copolymers have been prepared to form cocontinuous structure and host the nanoreinforcement. A high degree of dispersion of oriented clay was observed through X-ray diffraction, scanning, and transmission electron microscopy. This was confirmed by the solid-like behavior of storage modulus in low frequencies in rheological measurement results. An alteration in the morphology of blends was witnessed upon addition of clay where the transportation phenomenon to the copolymer phase resulted in a downsizing on the domain size of the constituents of the immiscible blends. The AC breakdown strength of nanocomposites significantly increased when clay was incorporated. The partially exfoliated and intercalated clay platelets are believed to distribute the electric stress and prolong the breakdown time by creating a tortuous path for charge carriers. However, the incorporation of clay has been shown to diminish the DC breakdown strength of nanocomposites, mostly due to the thermal instability brought by clay.



Synthesis of Gold Nanoparticles to Capture Lifelike Proteins: Application on the Multichannel Sensor Array Design

Tue, 09 Jan 2018 09:06:09 +0000

The chemical elements of proteins are similar to that of DNA (e.g., C, H, O, and N), and DNA shows different knotted architectures. So we imagine that proteins may show a wealth of highly complex structures, especially when proteins interact with each other. The imagination was proved by synthesizing gold nanoparticles (GNPs) to capture the lifelike protein structures. The optical responses (i.e., color) of as-prepared GNPs are found to be characteristic to a given protein (or heavy metal ion). Based on the “three colors” principle of Thomas Young, we extracted the red, green, and blue (RGB) alterations of as-synthesized GNPs to fabricate multichannel sensor arrays for proteins (or heavy metal ions) discrimination. The designed multichannel sensor arrays demonstrate possibilities in semiquantitative analysis of multiple analytes (e.g., proteins and heavy metal ions). This work is believed to open new opportunities for GNPs-based label-free sensing.



Room Temperature Detection of Acetone by a PANI/Cellulose/WO3 Electrochemical Sensor

Mon, 08 Jan 2018 08:24:35 +0000

Chemical sensing based on semiconducting metal oxides has been largely proposed for acetone sensing, although some major technical challenges such as high operating temperature still remain unsolved. This work presents the development of an electrochemical sensor based on nanostructured PANI/cellulose/WO3 composite for acetone detection at room temperature. The synthesized materials for sensor preparation were polyaniline (PANI) with a conductivity of 13.9 S/cm and tungsten trioxide (WO3) in monoclinic phase doped with cellulose as carbon source. The synthesized materials were characterized by high resolution transmission electron microscopy (HRTEM), X-ray diffraction (XRD), cyclic voltammetry (CV), and Raman spectroscopy. The composite was applied for acetone detection in the range of 0 to 100 ppmv at room temperature with electrochemical impedance spectroscopy (EIS) for monitoring resistance changes proportional to acetone concentration. The developed sensor achieved a calculated limit of detection of 10 ppm and of 0.99415 with a RSD of 5% () at room temperature. According to these results, the developed sensor is suitable for acetone sensing at room temperatures without the major shortcomings of larger systems required by high operating temperatures.



Multifunctional Amine Mesoporous Silica Spheres Modified with Multiple Amine as Carriers for Drug Release

Mon, 08 Jan 2018 00:00:00 +0000

Mesoporous silica spheres were synthesized by using Stöber theory (MSN-40). Calcination of the mesostructured phase resulted in the starting solid. Organic modification with aminopropyl groups resulted in two MSN-40 materials: named MSN-NH2 and MSN-DQ-40, respectively. These two kinds of samples with different pore sizes (obtained from 3-[2-(2-aminoethylamino)ethylamino]propyl-trimethox-ysilane (NQ-62) and modified NQ-62) showed control of the delivery rate of ibuprofen (IBU) from the siliceous matrix. The obtained sample from modified NQ-62 has an increased loading rate and shows better control of the delivery rate of IBU than the obtained sample from NQ-62. These three solids were characterized using standard solid state procedures. During tests of in vitro drug release, an interesting phenomenon was observed: at high pH (pH 7.45), IBU in all carriers was released slowly; at low pH (pH 4.5), only a part of the IBU was slowly released from this carrier within 25 hours; most IBU was effectively confined in mesoporous material, but the remaining IBU was released rapidly and completely after 25 hours.



Enhancement of Capacitive Performance in Titania Nanotubes Modified by an Electrochemical Reduction Method

Thu, 04 Jan 2018 07:06:27 +0000

Highly ordered titania nanotubes (TNTs) were synthesised by an electrochemical anodization method for supercapacitor applications. However, the capacitive performance of the TNTs was relatively low and comparable to the conventional capacitor. Therefore, in order to improve the capacitive performance of the TNTs, a fast and facile electrochemical reduction method was applied to modify the TNTs (R-TNTs) by introducing oxygen vacancies into the lattice. X-ray photoelectron spectroscopy (XPS) data confirmed the presence of oxygen vacancies in the R-TNTs lattice upon the reduction of Ti4+ to Ti3+. Electrochemical reduction parameters such as applied voltage and reduction time were varied to optimize the best conditions for the modification process. The electrochemical performance of the samples was analyzed in a three-electrode configuration cell. The cyclic voltammogram recorded at 200 mV s−1 showed a perfect square-shaped voltammogram indicating the excellent electrochemical performance of R-TNTs prepared at 5 V for 30 s. The total area of the R-TNTs voltammogram was 3 times larger than the unmodified TNTs. A specific capacitance of 11.12 mF cm−2 at a current density of 20 μA cm−2 was obtained from constant current charge-discharge measurements, which was approximately 57 times higher than that of unmodified TNTs. R-TNTs also displayed outstanding cycle stability with 99% capacity retention after 1000 cycles.



Hybrid Monolith of Graphene/TEMPO-Oxidized Cellulose Nanofiber as Mechanically Robust, Highly Functional, and Recyclable Adsorbent of Methylene Blue Dye

Wed, 03 Jan 2018 07:46:09 +0000

Herein we demonstrate first report on fabrication, characterization, and adsorptive appraisal of graphene/cellulose nanofibers (GO/CNFs) monolith for methylene blue (MB) dye. Series of hybrid monolith (GO/CNFs) were assembled via urea assisted self-assembly method. Hybrid materials were characterized by scanning electron microscopy, Fourier transform infrared spectroscopy, X-ray diffraction patterns, Raman spectroscopy, elemental analysis, thermogravimetric curve analysis, specific surface area, surface charge density measurement, and compressional mechanical analysis. It was proposed that strong chemical interaction (mainly hydrogen bonding) was responsible for the formation of hybrid assembly. GO/CNFs monolith showed mechanically robust architecture with tunable pore structure and surface properties. GO/CNFs adsorbent could completely remove trace to moderate concentrations of MB dye and follow pseudo-second-order kinetics model. Adsorption isotherm behaviors were found in the following order: Langmuir isotherm > Freundlich isotherm > Temkin isotherm model. Maximum adsorption capacity of 227.27 mg g−1 was achieved which is much higher than reported graphene based monoliths and magnetic adsorbent. Incorporation of nanocellulose follows exponential relationship with dye uptake capacities. High surface charge density and specific surface area were main dye adsorptive mechanism. Regeneration and recycling efficiency was achieved up to four consecutive cycles with cost-effective recollection and zero recontamination of treated water.



Preparation and Evaluation of Doxorubicin-Loaded Micelles Based on Glycyrrhetinic Acid Modified Gelatin Conjugates for Targeting Hepatocellular Carcinoma

Mon, 01 Jan 2018 09:48:09 +0000

Hepatocellular carcinoma (HCC) is one of the most prevalent fatal diseases and the incidence of HCC is increasing worldwide. Polymeric micelles with targeting groups have drawn great attention as carriers for drug delivery in HCC therapy. Herein, novel glycyrrhetinic acid modified gelatin (GA-GEL) conjugates with three substitution degrees were synthesized and characterized. Doxorubicin (DOX) was applied as a model drug. DOX-loaded GA-GEL (DOX/GA-GEL) micelles were prepared by an emulsion-solvent evaporation method. The mean diameters of DOX/GA-GEL micelles were in the range of 195–235 nm. The encapsulation efficiency of DOX/GA-GEL micelles was 63.6%–96.2%, and the loading content was 8.3%–12.5%. Drug release from DOX-loaded micelles exhibited a biphasic manner in phosphate buffer solution (PBS) at pH 7.4. DOX/GA-GEL could be efficiently accumulated into human liver cancer HepG2 cells. The IC50 values of DOX/GA-GEL-2 and DOX·HCl in HepG2 cells were 0.33 and 0.66 μg/mL, respectively. In vivo imaging analysis demonstrated that the fluorescence signals of DiR-labeled GA-GEL-2 micelles were mainly distributed in liver and H22 orthotopic tumor, indicating that GA-GEL had the liver-targeting activity. Compared to DOX·HCl, DOX/GA-GEL-2 exhibited better antitumor activity in H22 orthotopic mice. Therefore, these results indicated that GA-GEL could be used as carrier of hydrophobic drug for targeting HCC.



Antimicrobial Nanocomposites Prepared from Montmorillonite/Ag+/Quaternary Ammonium Nitrate

Mon, 01 Jan 2018 08:44:10 +0000

Nanocomposites of Ag with organic montmorillonite (Ag-OMMT), Ag with montmorillonite (Ag-MMT), and organic montmorillonite (OMMT) were successfully prepared via a one-step solution-intercalated method. Sodium MMT, silver nitrate, and dimethyl octadecyl hydroxy ethyl ammonium nitrate were used as precursors. X-ray diffraction, Fourier transform infrared spectroscopy, transmission electron microscopy, and energy dispersive spectroscopy analyses confirmed that the MMT layers were intercalated, and Ag+ was partly reduced to silver nanoparticles with diameters within 10–20 nm in Ag-OMMT. The decomposition temperature of the organic cations in OMMT and Ag-OMMT increased to 220°C, as revealed by differential scanning calorimetry-thermogravimetric analysis. The antimicrobial activity of the nanocomposites was tested by measuring the minimum inhibitory concentration (MIC) and killing rate. The MICs of Ag-OMMT against Staphylococcus aureus, Escherichia coli, and Candida albicans were 0.313, 2.5, and 0.625 mg/mL, respectively. Because of the presence of quaternary ammonium nitrate, Ag-OMMT has a better MIC against Gram-positive bacteria compared to Gram-negative bacteria and fungi. OMMT did not show antimicrobial activity against Escherichia coli and Candida albicans. In 2 h, 0.0125 mg/mL Ag-OMMT could kill 100% of S. aureus, E. coli, and C. albicans in solution, and Ag-MMT could kill 99.995% of S. aureus, 90.15% of E. coli, and 93.68% of C. albicans. These antimicrobial functional nanocomposites have the potential for application in the area of surface decoration films.



A Comparison of Pd0 Nanoparticles and Pd2+ Modified Bi2O2CO3 for Visible Light-Driven Photocatalysis

Mon, 01 Jan 2018 08:18:09 +0000

As two effective approaches to increase the visible light-absorption capacities of photocatalysts, ion doping and metallic nanoparticles loading are compared in this work. Palladium was selected to modify Bi2O2CO3. Compared to dispersing palladium nanoparticles on the photocatalyst surface, it was more effective for the method of doping with palladium to shift the energy level within the bandgap of Bi2O2CO3 in improving its photocatalytic activity under visible light. This might be because doping with Pd2+ narrows the band gap of Bi2O2CO3 so as to increase the absorption capacity of visible light photons. Pd nanoparticles on the other hand can absorb photons to produce electrons which are then utilized by Bi2O2CO3 for photocatalytic reactions. Different mechanisms resulted in significant differences, and this work provides solid evidence that ion doping may be a more effective method to improve the photocatalytic activity of Bi2O2CO3.



Bimetallic Oxide Nanohybrid Synthesized from Diatom Frustules for the Removal of Selenium from Water

Sun, 31 Dec 2017 11:46:43 +0000

Frustules or the rigid amorphous silica cell wall of unicellular, photosynthetic microalgae with unique porous architecture has been used to synthesize a composite by immobilizing zirconium and iron oxides on its surface and in the pores. This was effective for removal of Se from water, which is an emerging contaminant that is a micronutrient at low concentrations but toxic at high concentrations. The adsorption isotherms followed both Langmuir and Freundlich models, and the composite was regenerable. The Langmuir maximum adsorption capacity for Se(IV) was 227 mg/g, which is among the highest ever reported. The research findings highlight the synthesis of bimetallic composite as well as the potential of diatoms as hosts for nanomaterials for use in water treatment.



Preparation of Fe3O4/Reduced Graphene Oxide Nanocomposites with Good Dispersibility for Delivery of Paclitaxel

Sun, 31 Dec 2017 00:00:00 +0000

The Fe3O4/reduced graphene oxide (Fe3O4/RGO) nanocomposites with good dispersibility were synthesized for targeted delivery of paclitaxel (PTX). Firstly, the superparamagnetic Fe3O4/functional GO nanocomposites were prepared via hydrothermal method in which GO sheets were modified by surfactant wrapping. The Fe3O4/RGO nanocomposites were successively prepared through the reduction of graphene oxide. The products were investigated by Fourier-transform infrared spectrum, X-ray diffraction, scanning electron microscopy, transmission electron microscopy, thermogravimetric analysis, and vibration sample magnetometry. It was found that spherical Fe3O4 nanoparticles were uniformly anchored over the RGO matrix and the nanocomposites were superparamagnetic with saturation magnetization (Ms) of 9.39 emu/g. Then PTX was loaded onto Fe3O4/RGO nanocomposites, and the drug loading capacity was 67.9%. Cell viability experiments performed on MCF-7 demonstrated that the Fe3O4/RGO-loaded PTX (Fe3O4/RGO/PTX) showed cytotoxicity to MCF-7, whereas the Fe3O4/RGO displayed no obvious cytotoxicity. The above results indicated that Fe3O4/RGO/PTX nanocomposites had potential application in tumor-targeted chemotherapy.



Effect of Phosphate Buffered Saline Solutions on Top-Down Fabricated ZnO Nanowire Field Effect Transistor

Thu, 28 Dec 2017 00:00:00 +0000

ZnO based nanowire FETs have been fabricated by implementing a top-down approach, which uses optical photolithography, atomic layer deposition (ALD) of ZnO thin film, and anisotropic plasma etching. The effects of Phosphate Buffered Saline (PBS) solution on the surface of ZnO nanowire were investigated by measuring the FET characteristics at different PBS dilutions. The drain current, , exhibited an increase of 39 times in the highest PBS solution concentration compared to measurement in air. From the measured transfer characteristics and output characteristics in various PBS dilutions, the device was found to maintain n-type behaviour. These results indicate that the device can be effectively used for biomolecules sensing.






Relative Humidity Dependent Resistance Switching of Bi2S3 Nanowires

Mon, 25 Dec 2017 00:00:00 +0000

Electrical properties of Bi2S3 nanowires grown using a single source precursor in anodic aluminum oxide templates are sensitive to the relative humidity in an inert gas environment. Dynamic sensing dependency is obtained and shows presence of spontaneous resistance switching effect between low and high relative humidity states. Employing the thermionic field emission theory, heights of Schottky barriers are estimated from the current-voltage characteristics and in relation to the humidity response. The change of Schottky barrier height is explained by local changes in physically adsorbed water molecules on the surface of the nanowire.



Facile Preparation of Porous Inorganic SiO2 Nanofibrous Membrane by Electrospinning Method

Sun, 24 Dec 2017 10:02:09 +0000

We presented a straightforward method to fabricate porous inorganic SiO2 nanofibrous membrane by one-step calcination of electrospun nanofibers, which encapsulated with carbon nanospheres as template for nanopore generation. The structure, morphology, and composition of the as-spun fibers (PVA/SiO2/C) and porous SiO2 were characterized by Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), transmission electron microscopy (TEM), and scanning electron microscopy (SEM). The detective results indicated that the carbon nanospheres were uniformly encapsulated inside the PVA/SiO2/C nanofibers. After calcination, PVA polymer was removed and high flexible inorganic nanofibrous membrane composed of amorphous SiO2 was obtained. Simultaneously, carbon nanosphere template was decomposed and uniform nanopores were generated inside the SiO2 nanofibers. This new method is simple and of low cost and hence is suitable to prepare other porous inorganic nanofibers with high surface area for practical application.



Plant Explants Grown on Medium Supplemented with Fe3O4 Nanoparticles Have a Significant Increase in Embryogenesis

Wed, 20 Dec 2017 09:48:32 +0000

Development of nanotechnology leads to the increasing release of nanoparticles in the environment that results in accumulation of different NPs in living organisms including plants. This can lead to serious changes in plant cultures which leads to genotoxicity. The aims of the present study were to detect if iron oxide NPs pass through the flax cell wall, to compare callus morphology, and to estimate the genotoxicity in Linum usitatissimum L. callus cultures induced by different concentrations of Fe3O4 nanoparticles. Two parallel experiments were performed: experiment A, where flax explants were grown on medium supplemented with 0.5 mg/l, 1 mg/l, and 1.5 mg/l Fe3O4 NPs for callus culture obtaining, and experiment B, where calluses obtained from basal MS medium were transported into medium supplemented with concentrations of NPs identical to experiment A. Obtained results demonstrate similarly in both experiments that 25 nm Fe3O4 NPs pass into callus cells and induce low toxicity level in the callus cultures. Nevertheless, calluses from experiment A showed 100% embryogenesis in comparison with experiment B where 100% rhizogenesis was noticed. It could be associated with different stress levels and adaptation time for explants and calluses that were transported into medium with Fe3O4 NPs supplementation.



Carbon Nanoparticles Based Electrochemical Biosensor Strip for Detection of Japanese Encephalitis Virus

Mon, 18 Dec 2017 06:59:53 +0000

We reported a disposable and sensitive electrochemical biosensor strip based on carbon nanoparticles modified screen-printed carbon electrode (SPCE) for rapid and sensitive detection of Japanese Encephalitis Virus (JEV). Amino group functionalized carbon nanoparticles were prepared from preformed chitosan nanoparticles. Japanese Encephalitis Virus (JEV) antibody was immobilized onto the surfaces of carbon nanoparticles through amide bonds formation between amino groups of carbon nanoparticles and carboxylic groups of JEV antibody. The analytical performance of SPCE electrochemical biosensor strip was characterized using cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). SPCE electrochemical biosensor strip exhibited a linear detection range of 1–20 ngmL−1 with a low detection limit of 0.36 ngmL−1 (at S/N = 3) for JEV, detection sensitivity was 0.024 ngmL−1 for JEV, and analysis results were obtainable within 10 minutes. The potential clinical application of this SPCE electrochemical biosensor strip was demonstrated by the detection of JEV in human serum.



Efficient Preparation and Performance Characterization of the HMX/F2602 Microspheres by One-Step Granulation Process

Mon, 18 Dec 2017 06:57:24 +0000

A new one-step granulation process for preparing high melting explosive- (HMX-) based PBX was developed. HMX/F2602 microspheres were successfully prepared by using HMX and F2602 as the main explosive and binder, respectively. The particle morphology, particle size, crystal structure, thermal stability, and impact sensitivity of the as-prepared HMX/F2602 microspheres were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), laser particle size analyzer, differential scanning calorimetry (DSC), and impact sensitivity test, respectively. The SEM analysis indicated successful coating of F2602 on the surface of HMX, and the resulting particles are ellipsoidal or spherical with a median particle size of 940 nm; the XRD analysis did not show any change in the crystal structure after the coating and still has β-HNX crystal structure; according to the DSC analysis, HMX/F2602 prepared by the new method has better thermal stability compared to that prepared by the water suspension process. The impact sensitivity of HMX/F2602 prepared by this one-step granulation process decreased, and its characteristic height H50 increased from 37.62 to 40.13 cm, thus significantly improving the safety performance. More importantly, this method does not need the freeze-drying process after recrystallization, thus increasing the efficiency by 2 to 3 times.



Characterization of Ag-Doped p-Type SnO Thin Films Prepared by DC Magnetron Sputtering

Mon, 18 Dec 2017 00:00:00 +0000

Crystalline structure and optoelectrical properties of silver-doped tin monoxide thin films with different dopant concentrations prepared by DC magnetron sputtering are investigated. The X-ray diffraction patterns reveal that the tetragonal SnO phase exhibits preferred orientations along (101) and (110) planes. Our results indicate that replacing Sn2+ in the SnO lattice with Ag+ ions produces smaller-sized crystallites, which may lead to enhanced carrier scattering at grain boundaries. This causes a deterioration in the carrier mobility, even though the carrier concentration improves by two orders of magnitude due to doping. In addition, the Ag-doped SnO thin films show a p-type semiconductor behavior, with a direct optical gap and decreasing transmittance with increasing Ag dopant concentration.



Synthesis and Bactericidal Properties of Hyaluronic Acid Doped with Metal Nanoparticles

Sun, 17 Dec 2017 08:34:10 +0000

A study on the nanoparticles size and the antibacterial properties of hyaluronic acid (HA) doped with nanoparticles is reported. Nanoparticles from gold, silver, copper, and silver palladium with HA support were performed. The solvated metal atom dispersion (SMAD) method with 2-propanol and HA was used. High-resolution transmission electron microscopy (HRTEM), infrared spectroscopy (FT-IR), and thermogravimetric analysis (TGA) were conducted. The average sizes of nanoclusters were as follows: HA-Au = 17.88 nm; HA-Ag = 50.41 nm; HA-Cu = 13.33 nm; and HA-AgPd = 33.22 nm. The antibacterial activity of solutions and films containing nanoparticles against American Type Culture Collection (ATCC) bacterial strains Escherichia coli (EC), Staphylococcus aureus (SA), Staphylococcus epidermidis (SE), and Pseudomonas aeruginosa (PA) was determined. Inhibition was observed for HA-Ag, HA-Cu, and HA-AgPd. Toxicological tests were performed in rats that were injected intraperitoneally with two concentrations of gold, copper, silver, and silver-palladium nanoparticles. No alterations in hepatic parameters, including ALT (alanine aminotransferase), GGT (gamma-glutamyl transpeptidase) bilirubin, and albumin, were observed after 14 days. These films could be used as promoters of skin recovery and Grades I and II cutaneous burns and as scaffolds.



Fabrication, Characterization, and In Vivo Evaluation of Famotidine Loaded Solid Lipid Nanoparticles for Boosting Oral Bioavailability

Thu, 14 Dec 2017 07:39:59 +0000

Famotidine as H2 receptor has antagonistic effects on gastric secretion. Unfortunately, its hydrophobic nature contributes to its variable and poor oral bioavailability. In the current study efforts are being made to fabricate famotidine loaded solid lipid nanoparticles with narrow size distribution. Prepared nanoformulations were pharmaceutically evaluated to confirm the desired boosted oral bioavailability. Famotidine loaded nanoformulation (FFSe-4) showed particle size  nm, polydispersity index , zeta potential − mV, entrapment efficiency %, and drug loading capacity %. Drug-excipients compatibility was confirmed by Fourier transformed infrared spectroscopy. Scanning electron microscopy confirmed spherical shaped, nanosized particles. Differential scanning calorimetry and powder X-ray diffractometry confirmed the change in crystalline nature. Prepared nanoformulation was more stable at refrigerated temperature. In vitro study showed that drug release time is proportional to drug pay load and followed zero order kinetics. Release exponent () confirmed non-Fickian-diffusion mechanism for drug release. In vivo pharmacokinetic studies showed 2.06-fold increase in oral bioavailability of famotidine dispersed in solid lipid nanoparticles compared to commercial product. These results authenticate solid lipid nanoparticles as drug delivery system and propose prolonged release with improved oral bioavailability for famotidine.