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 Applied Nanoscience   [7 followers]  Follow       Open Access journal    ISSN (Print) 2190-5509 - ISSN (Online) 2190-5517    Published by SpringerOpen  [224 journals]
• Dual mechanism-based sensing of mercury using unmodified,
heteroepitaxially synthesized silver nanoparticles

• Abstract: Mercury and its compounds are widely distributed in the environment and have a significant negative impact on human health. In this paper, we report the development of a rapid and facile method for the detection of mercury ions (Hg2+) using heteroepitaxially synthesized unmodified silver nanoparticle-based smart probes using UV–Vis spectrophotometer and also through the naked eye by means of a paper-based sensor strip. The silver nanoparticles were prepared by heteroepitaxial growth method using gold seed nanoparticle of ~2.4 nm size as the template. The silver is grown on the seed particles by reducing the silver–ammonia complex using glucose, which resulted in Glu–AgNPs having an average size of 14.65 ± 3.53 nm. The sensing of mercury ions was carried out in aqueous solution and the reaction response was monitored by UV–Vis spectrophotometer. The interaction of Hg2+ with Glu–AgNPs resulted in a significant drop in the absorbance at 402 nm along with a prominent color change (from bright yellow to colorless) and wavelength shift (blue shift). The limit of detection (LOD) of this assay was found to be 100 nM (i.e., 20 ppb) with a good linearity in the concentration range of 100–10 mM. To further ease the detection process and make it field deployable, we attempted to develop a paper-based sensor strip by immobilizing Glu–AgNPs on a paper strip. Upon interaction with mercury solution of varying concentrations, the decoloration of the spots could be observed easily through naked eyes, with the limit of detection under sub-optical conditions being 1 µM.
PubDate: 2017-06-08

• Non-enzymatic detection of glucose in fruits using TiO 2 –Mn 3 O 4
hybrid nano interface

• Abstract: Consumption of fruits leads to increase in glucose level in blood for diabetic patients, which in turn leads to peripheral, vascular, ocular complications and cardiac diseases. In this context, a non-enzymatic hybrid glucose biosensor was fabricated for the first time to detect glucose by immobilizing titanium oxide–manganese oxide (TiO2–Mn3O4) nanocomposite and chitosan membrane on to the surface of Pt working electrode (Pt/TiO2–Mn3O4/chitosan). TiO2–Mn3O4 nanocomposite catalyzed the oxidation of glucose to gluconolactone in the absence of glucose oxidase enzyme with high electron transfer rate, good biocompatibility and large surface coverage. Electrochemical measurements revealed the excellent sensing response of the developed biosensor towards glucose with a high sensitivity of 7.073 µA mM−1, linearity of 0.01–0.1 mM, low detection limit of 0.01 µM, reproducibility of 1.5% and stability of 98.8%. The electrochemical parameters estimated from the anodic process were subjected to linear regression models for the detection of unknown concentration of glucose in different fruit samples.
PubDate: 2017-06-03

• A lucrative chemical processing of bamboo leaf biomass to synthesize
biocompatible amorphous silica nanoparticles of biomedical importance

• Abstract: Synthesis of silica nanoparticles from natural resources/waste via cost effective route is presently one of the anticipating strategies for extensive applications. This study reports the low-cost indigenous production of silica nanoparticles from the leftover of bamboo (leaf biomass) through thermal combustion and alkaline extraction, and examination of physico-chemical properties and yield percentage using comprehensive characterization tools. The outcome of primed silica powder exhibits amorphous particles (average size: 25 nm) with high surface area (428 m2 g−1) and spherical morphology. Despite the yield percentage of silica nanoparticles from bamboo leave ash is 50.2%, which is less than rice husk ask resources (62.1%), the bamboo waste is only an inexpensive resource yielding high purity (99%). Synthesis of silica nanoparticles from natural resources/waste with the help of lucrative route is at present times one of the anticipating strategies for extensive applications. In vitro study on animal cell lines (MG-63) shows non-toxic nature of silica nanoparticles up to 125 µg mL−1. Hence, this study highlights the feasibility for the mass production of silica nanoparticles from bamboo leave waste rather using chemical precursor of silica for drug delivery and other medical applications.
PubDate: 2017-06-01

• Silver nano fabrication using leaf disc of Passiflora foetida Linn

• Abstract: The main purpose of the experiment is to develop a greener low cost SNP fabrication steps using factories of secondary metabolites from Passiflora leaf extract. Here, the leaf extraction process is omitted, and instead a leaf disc was used for stable SNP fabricated by optimizing parameters such as a circular leaf disc of 2 cm (1, 2, 3, 4, 5) instead of leaf extract and grade of pH (7, 8, 9, 11). The SNP synthesis reaction is tried under room temperature, sun, UV and dark condition. The leaf disc preparation steps are also discussed in details. The SNP obtained using (1 mM: 100 ml AgNO3+ singular leaf disc: pH 9, 11) is applied against featured room temperature and sun condition. The UV spectroscopic analysis confirms that sun rays synthesized SNP yields stable nano particles. The FTIR analysis confirms a large number of functional groups such as alkanes, alkyne, amines, aliphatic amine, carboxylic acid; nitro-compound, alcohol, saturated aldehyde and phenols involved in reduction of silver salt to zero valent ions. The leaf disc mediated synthesis of silver nanoparticles, minimizes leaf extract preparation step and eligible for stable SNP synthesis. The methods sun and room temperature based nano particles synthesized within 10 min would be use certainly for antimicrobial activity.
PubDate: 2017-06-01

• Study on effects of E-glass fiber hybrid composites enhanced with
multi-walled carbon nanotubes under tensile load using full factorial
design of experiments

• Abstract: Carbon nanotubes (CNT’s) are attracting scientific and industrial interest by virtue of their outstanding characteristics. The present research problem deals with the fabrication and characterization of E-glass fiber composites enhanced by carbon nanotubes. In the present study, three factors with two levels are considered. Hence, the design is called 23 full factorial design of experiment. The process parameters considered for the present problem are weight of multi-walled carbon nanotubes, process to disperse nano-particles in resin, and orientation of woven fabric. In addition, their levels considered for the experiment are higher level (+1) and lower level (−1). Fabrication of E-glass fiber composites was carried out according to design, and the specimens were prepared with respect to the ASTM standards D3039-76 and tensile testing was performed. The results show that the nano-particulated composite plate can be manufactured by considering lower level nano-particles stirred with probe sonicator and plied-up with hybrid orientation.
PubDate: 2017-05-20

• DNA–carbon nano onion aggregate: triangle, hexagon, six-petal flower

• Abstract: The interaction between calf-thymus (CT) dsDNA and water soluble carbon nano onion (wsCNO) in water follows denaturation of dsDNA (double stranded) to ssDNA (single stranded) as monitored by optical spectroscopy. The ssDNA concomitantly wraps the spiky surface of wsCNO to create triangular aggregate as the building block as observed by time-dependent SEM images. These triangles further aggregate leading to six-petal flower arrangement via hexagon and finally reach a dead end network as imaged by SEM and optical fluorescence microscopy. The dead-end network aggregate lost the intrinsic optical property of DNA suggesting complete loss of its activity.
PubDate: 2017-05-17

• A study of the optical band gap of zinc phthalocyanine nanoparticles using
UV–Vis spectroscopy and DFT function

• Abstract: In the present work, we used the ultraviolet–Visible (UV–Vis) spectroscopy technique to find the optical band gap of zinc phthalocyanine nanoparticles (ZnPc-NP) experimentally. Moreover, we used a time-dependent density functional theory (TDDFT) to simulate the UV–Vis absorption spectrum of ZnPc molecule in gas and solution phases. The ZnPc-NP absorption spectrum shows a shift toward higher energies compared to the bulk ZnPc. The simulated UV–Vis and the experimental nanoparticle’s spectrum were found to have a good agreement. The ZnPc energy band gap from the DFT calculations shows how it’s possible to get wider range of energy band gap for the ZnPc. The ZnPc-NP’s size and shape were examined using the transmission electron microscope (TEM).
PubDate: 2017-04-27

• Blood flow analysis with considering nanofluid effects in vertical channel

• Abstract: Manipulation of heat convection of copper particles in blood has been considered peristaltically. Two-phase flow model is used in a channel with insulating walls. Flow analysis has been approved by assuming small Reynold number and infinite length of wave. Coupled equations are solved. Numerical solution are computed for the pressure gradient, axial velocity function and temperature. Influence of attention-grabbing parameters on flow entities has been analyzed. This study can be considered as mathematical representation to the vibrance of physiological systems/tissues/organs provided with medicine.
PubDate: 2017-04-25

• Photocatalytic degradation of methyl orange dye by pristine titanium
dioxide, zinc oxide, and graphene oxide nanostructures and their

• Abstract: Discharge of azo dyes by textile and allied industries to the environment is a growing problem. Degradation of an azo dye, methyl orange (MO), was tested in simulated wastewater with different oxide nanomaterials acting as photocatalysts under visible light. Titanium dioxide (TiO2), zinc oxide (ZnO), and graphene oxide (GO) were synthesized, characterized, and applied for adsorptive and photocatalytic removal of the dye. Factors such as initial concentration of MO and size of nanoparticle photocatalyst were varied to determine the optimum conditions for dye removal. Finally, nanocomposites of the three materials (GO–TiO2–ZnO) were synthesized and tested for its photocatalytic performance. The composition of the individual oxide in the nanocomposite was then varied to achieve the best photocatalytic performance.
PubDate: 2017-04-22

• Effect of Mg doping and sintering temperature on structural and
morphological properties of samarium-doped ceria for IT-SOFC electrolyte

• Abstract: Samples of Sm and Mg co-doped ceria electrolyte of Ce1−x Sm x−y Mg y O2−δ (x = 0.2; y = 0.00, 0.05, 0.1, 0.15, and 0.175) were synthesized by sol–gel process. The prepared samples were sintered at 1100 and 1400 °C for 4 h. The bulk densities were measured by Archimedes method. XRD measurements indicate that the synthesized samples were in single-phase cubic fluorite structure (space group Fm3m). The cell parameters decrease with the concentration of Mg, and 2θ values slightly shift towards right. The particle sizes obtained were between 7.14 and 17.44 nm. The sintered sample achieved 95% of theoretical density. FTIR spectra of samples sintered at 1400 °C indicates weak interactions between 3550–3400 cm−1 and 1600–1300 cm−1 are attributed to O–H stretching modes and strong bonds 850–450 cm−1 are assigned to characteristic Ce–O vibrations. The surface morphology and chemical composition were analyzed by SEM and EDS, SEM micrographs show spherical faceted grains, and the samples were crack free, dense material with some pores on surface which are inconsistent with density results. The average grain size obtained was 0.5 μm. Particle size obtained by TEM was in agreement with that obtained by XRD. The high-density ceria co-doped ceramic can be used as electrolyte in SOFC.
PubDate: 2017-04-21

• Synthesis and magnetic induction heating properties of Gd-substituted
Mg–Zn ferrite nanoparticles

• Abstract: Gadolinium-substituted magnesium–zinc ferrite (Mg x Zn1−x Gd y Fe2−y O4) nanoparticles with different metal compositions for x between 0 and 1 and y between 0 and 0.06 were synthesized via coprecipitation of metal hydroxides, followed by calcination. Their crystal structure was characterized via X-ray diffraction analysis, confirming that the Gd-substituted Mg–Zn ferrite samples had a single-phase spinel structure. The metal composition significantly affected the crystal structure, including the lattice parameters and crystallite size. Scanning electron microscopy (SEM) showed that the ferrite samples had a diameter of approximately 50–200 nm. Furthermore, the temperature rise in an alternating magnetic field was measured, and the magnetic induction heating properties were evaluated using the specific absorption rate (SAR) determined from the temperature profile. The SAR significantly varied depending on the compositions of x and y. When x = 0.5 and y = 0.02, the SAR was found to be at maximum. This reveals that the compositions can control the magnetic induction heating properties. The results suggest that Gd-substituted Mg–Zn ferrite nanoparticles are promising candidates for magnetic hyperthermia applications.
PubDate: 2017-04-19

• A molecular dynamics investigation into the adsorption behavior inside
{001} kaolinite and {1014} calcite nano-scale channels: the case with
confined hydrocarbon liquid, acid gases, and water

• Abstract: A set of molecular dynamics simulations was conducted, as the first comparative study of the adsorption behavior of liquid hydrocarbon/acid gases/water molecules over $$\{ 10\bar{1}4\}$$ calcite surface and {001} octahedral kaolinite surface in nano-confined slit. According to atomic z-density profiles, hydrocarbon molecules have higher tendency towards the $$\{ 10\bar{1}4\}$$ calcite surface than the {001} octahedral kaolinite surface. In addition, water molecules form stronger adsorption layer over calcite surface than kaolinite. In contrast, acid gas molecules have higher tendency towards kaolinite surface than calcite. This behavior was spotted within nanometer-sized slit pores. The results also point to reduction in self-diffusion coefficient of molecules with strong adsorption over mineral surfaces in nano-confined environment.
PubDate: 2017-04-12

• Sonication-assisted synthesis of polystyrene (PS)/organoclay
nanocomposites: influence of clay content

• Abstract: This article presents the synthesis of a series of polystyrene (PS)/organoclay nanocomposite films consisting of different contents of clay (1–7 wt%) by sonication-coupled solvent-blending technique. The prepared PS nanocomposite films were characterized using various techniques, including X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), transmission electron microscopy (TEM), and thermal gravimetric analysis (TGA). The XRD and TEM results revealed the formation of exfoliated nanocomposites at lower loading of organoclay (<5 wt%). The presence of various functional groups in the organoclay and PS/organoclay nanocomposite was verified by FTIR spectra. The thermal stability of PS nanocomposites was significantly improved as compared to pristine PS, which is evident from TGA analysis. When 10% mass loss was chosen as a point of reference, the thermal degradation temperature of PS nanocomposite holding 7 wt% of organoclay was found to be 30 °C more over pristine PS. The thermal kinetic parameters such as activation energy (E a), pre-exponential factor (A), and the order of reaction (n) were determined by employing the Coats–Redfern model. Thermal degradation reaction mechanism of PS nanocomposites was also investigated.
PubDate: 2017-04-11

• Optimized interaction parameters for metal-doped endohedral fullerene

• Abstract: Interaction between various atoms doped inside C60 can be modeled using interaction potentials and, thus, cohesive energy and other physical constants may be calculated. In case of metal-doped fullerene total energy may be written in terms of three different types of interactions, namely carbon–carbon interaction, metal–metal interaction and carbon–metal interaction. Brenner potential, Gupta potential, and Lennard–Jones potentials have been used to model these interactions respectively. Generally, parameters used in these model potentials are not readily available and need to be fine-tuned for different dopants. In this paper, we have deduced/optimized these interaction parameters for Cu, Ag, Al and Ga doped C60 comparing with our Density Functional Theory (DFT) results and hence predicting the stability of various metal-doped fullerenes. Total energy calculations reveal that a maximum of nine copper atoms can be doped inside the fullerene cage and form stable complex without distorting the cage significantly. As we add more number of Cu atoms in the fullerene molecule, cage structure breaks down. In the same way, we have done calculations for Ag, Al and Ga atoms doped inside the fullerene molecule and found that the maximum of eight, nine, nine atoms can form stable complexes.
PubDate: 2017-04-10

• ZnO nanoparticles (ZnO-NPs) and their antifungal activity against coffee
fungus Erythricium salmonicolor

• Abstract: In this work, a methodology of synthesis was designed to obtain ZnO nanoparticles (ZnO NPs) in a controlled and reproducible manner. The nanoparticles obtained were characterized using infrared spectroscopy, X-ray diffraction, and transmission electron microscopy (TEM). Also, we determined the antifungal capacity in vitro of zinc oxide nanoparticles synthesized, examining their action on Erythricium salmonicolor fungy causal of pink disease. To determine the effect of the quantity of zinc precursor used during ZnO NPs synthesis on the antifungal capacity, 0.1 and 0.15 M concentrations of zinc acetate were examined. To study the inactivation of the mycelial growth of the fungus, different concentrations of ZnO NPs of the two types of synthesized samples were used. The inhibitory effect on the growth of the fungus was determined by measuring the growth area as a function of time. The morphological change was observed with high-resolution optical microscopy (HROM), while TEM was used to observe changes in its ultrastructure. The results showed that a concentration of 9 mmol L−1 for the sample obtained from the 0.15 M and at 12 mmol L−1 for the 0.1 M system significantly inhibited growth of E. salmonicolor. In the HROM images a deformation was observed in the growth pattern: notable thinning of the fibers of the hyphae and a clumping tendency. The TEM images showed a liquefaction of the cytoplasmic content, making it less electron-dense, with the presence of a number of vacuoles and significant detachment of the cell wall.
PubDate: 2017-04-09

• Enhance the figure of merit for flexible thermoelectric materials by
reducing the screening effect

• Abstract: A flexible thermoelectric materials (FTEM) films based on Polydimethylsiloxane as the polymer matrix and (Zinc Oxide, Polyaniline and multi wall Carbon nanotube) as the fillers were prepared. The fillers were prepared using modified sol–gel method to enhance the distribution of the nanoparticles inside the polymer matrix and good performance. The Seebeck coefficient, electrical conductivity, thermal conductivity and dielectric measurements were carried out for all of the four films. The Seebeck coefficient results for the investigated films were −40, 220, −120, 280 μv/k° at 200 °C for FTEM 1, 2, 3, 4 alternatively. The sign and the value for the Seebeck measurements show a great dependent on the filler type add to the film. The electrical conductivity results for the films was varied from 2 × 10−8 to 0.14 S/m and strongly dependent on the fillers electrical conductivity. The less dependent on the thermal conductivity of the fillers and a slight change in the thermal conductivity value of the films were obtained. The figure of merit for the films was ranged from 1.14 × 10−16 to 3.134 × 10−8. The dielectric results ranged from 4 to 3500. Reducing the screening effect will increase the electrical conductivity and Seebeck coefficient values.
PubDate: 2017-04-07

• Assessment of toxicity in fresh water fish Labeo rohita treated with
silver nanoparticles

• Abstract: Silver nanoparticles (17.78 ± 12.12 nm) were synthesized by the reduction of 0.5 M silver nitrate using formaldehyde as reducing and triethylamine as promoting and stabilizing agent. The particles were grain like agglomerates with spherical, centered-face cubic and crystalline in nature. The sample was highly pure with amine (NH) as associated and capping molecules. Further, the genotoxicity and oxidative stress of these particles were evaluated using Labeo rohita (L. rohita) as genetic model exposed (10–55 mg L−1 dose) through aquatic medium for 28 days. The cells were produced with micronuclei, fragmented, lobed and buds nuclei in dose dependent manner. The highest incidence of comet was recoded (27.34 ± 5.68) at 55 mg L−1 Ag-NPs and 14 days treatment. Then frequency was decreased to 22.65 ± 6.66% after 28 days due to complex repair mechanism. Moreover, the treatment also produces the oxidative stress and disturbs the level of GST in gill and liver tissue. There was a sharp decline in the activities of GST and this decrease of activity increase the MDA content. Further, the elevated level of GSH represents that the liver has started defensive mechanism against oxyraidcals. This study concluded, Ag-NPs are genotoxic in nature and produce micronuclei, comet cells and also induces oxidative stress in aquatic organisms.
PubDate: 2017-04-05

• Sonochemical synthesis of novel magnesium 1,2,4-triazole-1-carbodithioate
nanoparticles as antifungals

• Abstract: Novel magnesium 1,2,4-triazole-1-carbodithioates were sonochemically synthesized as water-dispersable nanoparticles owing to their water insolubility. The two-step reaction protocol was followed to synthesize the novel triazole ligand system for complexation with magnesium metal due to its low biological toxicity. Different concentrations of Poly Vinyl Pyrrolidine were used to stabilize and standardise the size of nanoparticles, which were characterised by TEM analysis. UV–Visible and infrared spectroscopies were used to analyse the metal ligand interaction, and CHNS analysis was used to propose the structure of the metal complex. The spore germination inhibition technique was used to evaluate the antifungal potential of synthesized nano-complexes against two phytopathogenic test fungi viz. A. alternata and F. moniliforme. The nanoparticles had inflicted moderate in vitro inhibition of fungal growth, which was comparable to standard fungicide Indofil M-45. The in silico toxicity of the compounds was made using the Toxtree analysis software that indicated the compounds belong to class III group of toxicity, which was same as that of commercial standards of DTC.
PubDate: 2017-03-11

• Self-assembled nanotubes from single fluorescent amino acid

• Abstract: Self-assembly of biomolecules has gained increasing attention as it generates various supramolecular structural assemblies having potential applications principally in biomedical sciences. Here, we show that amino acid like tryptophan or tyrosine readily aggregates as nanotubes via a simple self-assembly process. These were characterized by FTIR, scanning electron microscopy, and by fluorescence microscopy. Nanotubes prepared from tryptophan are having ~200 nm inner diameter and those from tyrosine are having the same around ~50 nm diameter.
PubDate: 2017-03-01

• A new approach for orientation-controlled growth of CNTs: an in-depth
analysis on the role of oxygen plasma treatment to catalyst

• Abstract: In this paper, a novel and easy technique is proposed for orientation controlled growth of MWNTs. The results indicate that when CNT growth was carried over the substrate, not treated with plasma, horizontal network of MWNTs was formed. Plasma treatment to the substrate prior to CNTs growth led to formation of vertically aligned MWNTs. An in situ growth as a function of plasma treatment time reveals the mechanism behind this flip process. All experiments were performed under atmospheric pressure. At every step during time-dependent growth process, CNTs were characterized using FESEM, HRTEM, and Raman spectroscopy. Iron sputtered silicon substrate was also investigated to validate the excellent formation of as-grown vertical CNTs and also to analyze the role of oxygen plasma behind the orientation-controlled growth. The as-grown CNTs over the iron sputtered silicon substrate with or without plasma treatment were characterized by FESEM and AFM. The successful orientation-controlled growth of CNTs was achieved.
PubDate: 2017-02-20

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