Journal of Nano Structures
Volume:8 Issue: 2, Spring 2018

Biological synthesis of zinc sulfide (ZnS) nanoparticles (NPs) was prepared by a simple co-precipitation method using methanol plant extracts of Tridax procumbens, Phyllanthusniruri, and Syzygium aromaticum. The as-prepared ZnS NPs was examined by several physiochemical techniques such as X-Ray Powder Diffraction (XRD), Scanning Electron Microscopy (SEM), UV-Visible spectroscopy, Fourier Transform infrared spectroscopy analysis (FTIR). The disk diffusion method was used to screen the antimicrobial activity of Pure and Plant extracts doped ZnS NPs against different gram positive, gram-negative bacteria and fungus culture. From this investigation synthesized ZnS NPs have a potential antimicrobial agent where showed a hot zone of inhibition (ZOI) at different concentration against all tested microorganisms. Biosynthesized ZnS NPs Photocatalytic degradation also evaluated for Methylene Blue Dye (MBD) and Methyl Orange Dye (MOD) degradation in aqueous solution under UV Light irradiation. Due to the smaller particles size, narrowing optical band gap and antimicrobial properties of synthesised ZnS NPs were improve the photocatalytic activity. Here we first time reported Syzygium aromaticum methanol extracts ZnS NPs exhibited excellent efficiency in Methylene Blue Dye (MBD) and Methyl Orange Dye (MOD) degradation with comparing other ZnS NPs.

In this work we report preparation TiO2 hollow spheres and its application as an electrochemical sensor. Therefore the novel carbon paste electrode modified with TiO2 hollow spheres (TOHS), multi-walled carbon nanotubes (MWCNTs) and poly-glutamic acid (PGA) film (PGA/TOHS/MWCNTs/CPE) was used for simultaneous determination of dopamine (DA) and piroxicam (PRX) in the presence of ascorbic acid (AA). The electro-oxidation of dopamine(DA) and piroxicam (PRX) has been investigated by application of the modified electrode using cyclic voltammetry (CV), differential pulse voltammetry (DPV) and chronoamperometry (CA) methods. The modified electrode accelerates the electron transfer reactions of DA and PRX. In addition it shows no significant interference of AA as the electroactive coexistent compounds with DA and PRX in biological systems. The fabricated sensor revealed some advantages such as excellent selectivity, good stability and high sensitivity toward DA and PRX determination. Under the optimum conditions the electrode provides a linear response versus DA and PRX concentrations in the range of 0.3–60 and 0.4–80 µM and with a detection limit of 0.2µM and 0.3µM(S/N=3) respectively using the DPV method. The modified electrode was used for determination of DA and PRX in human urine with satisfactory results.

The preparation of polyaniline/zeolite nanocomposite coating on 304 stainless steel (304 SS) surface has studied via the galvanostatic method. The electro-generated coating was characterized by Fourier transform infrared spectroscopy (FT-IR), UV-visible absorption spectroscopy, X-ray diffraction (XRD) patterns and scanning electron microscopy (SEM). The anticorrosion property of polyaniline/zeolite nanocomposite coating was explored in 0.5 M hydrochloric acid solution by Tafel polarization method and electrochemical impedance spectroscopy (EIS). The effect of variable parameters such as the applied current density and deposition time on the corrosion protection of the electro-generated coatings was also considered. The corrosion rate of coated-304 SS was releazied about 36 times lower than bare 304 SS. Potential of corrosion also changed from -0.411 V to -0.279 V versus Ag/AgCl for un-coated and coated-304 SS electrodes, respectively. Electrochemical measurements indicate that polyaniline/zeolite nanocomposite coated on 304 SS has remarkable inhibitive properties with protection effectiveness of ~97% at 2.5 mA cm-2 current density used on 304 SS in acidic medium. The outcomes of this research obviously find out that the polyaniline/zeolite nanocomposite has an outstanding possible to defend 304 SS against corrosion in an acid environment.

CeVO4 (Cerium orthovanadate) nanoparticles were synthesized by urea-assisted simple and efficient combustion method. Phase formations of synthesized nanoparticles were characterized by thermogravimetric-differential thermal analyzer (TG-DTA). X-ray diffraction (XRD) pattern revealed the crystal planes and size of synthesized CeVO4 nanoparticles. The average size, morphological shape and the crystalline nature of the nanoparticles were determined by scanning electron microscopy (SEM), transmission electron microscopic with selected area electron diffraction (TEM-SAED). Energy-dispersive X-ray spectroscopy (EDX) confirmed the presence of elemental composition and purity of the synthesized nanoparticles. Fourier transform Infrared spectroscopy (FT-IR) confirmed the possible stretching frequency on the surface of CeVO4 nanoparticles. Surface area and porosity studies of synthesized nanoparticles were analyzed by Brunauer-Emmett-Teller (BET) and Barrett-Joyner-Halenda (BJH) curve. Moreover, CeVO4 nanoparticles evinced excellent antibacterial activity against Escherichia coli, Klebsiella pneumoniae, Pseudomonas aeruginosa, Proteus vulgaris, Salmonella typhi, Staphylococcus aureus, Streptococcus pyogenus, Bacillus subtilis, Streptococcus pneumoniae and Staphylococcus epidermidis. The studies describing the synthesis of CeVO4 nanoparticles by efficient combustion method followed by the investigation of antibacterial activities may be useful for research opening a new arena in the field of nanobiotechnology.

This present work reports an ecofriendly approach for the synthesis of gold nanoparticles (Au NPs) using aqueous stem extract of Periploca aphylla as a reducing and stabilizing agent, has been discussed. This approach is simple, cost-effective and stable for a long time, reproducible at room temperature and in an eco-friendly manner to obtain a self-assembly of Au NPs. Two parameters were optimised for the fabrication of gold nanoparticles including the pH and contact time. The resulting nanoparticles are characterized using UV–vis, TEM, XRD and FT-IR spectroscopic techniques. UV–visible spectra of the aqueous medium containing gold nanoparticles showed a surface plasmon resonance peak at 535 nm. Uniform spherical shapes were observed for biosynthesized Au NPs within range of 25–30 nm by transmission electron microscopy. XRD results confirmed the presence of gold nanoparticles with face centered cubic structure. FT-IR analysis was performed to analyze the biomolecules responsible for the reduction of Au NPs.

This paper describes synthesis of In2S3 nanoparticles by sonochemistry method and their application to enhance solar cells performance which In2S3 nanoparticles work as co-sensitizer for the first time. In2S3 is a narrow band gap semiconductor (2 eV) with conduction band higher than TiO2. Therefore it can transfer electron to the conduction band of TiO2. The effect of different parameters such as power and time on size of products were investigated. The fabricated solar cells made by different samples in the same conditions shown different Jsc, Voc, FF and efficiency. Modified dye sensitized solar cells (DSSC) exhibits the best performance with the power conversion efficiency of 8 % which is superior to that of the free–modified DSSC with the photoelectric conversion efficiency (PCE) of 5.1%. Modified solar cell shows 56.7% improvement in the efficiency. The prepared Nanoparticles and fabricated solar cells were characterized by X-ray diffraction (XRD), energy dispersive X-ray spectroscopy (EDX), scanning electron microscopy (SEM) and I-V measurement.

Trypsin (E.C.3.4.21.4) is a serine protease commonly used in proteomics for digestion of proteins. In the present study, the effect of nano-TiO2 on the conformation and catalytic activity of trypsin were studied. The thermal denaturation of trypsin has been investigated in the presence and absence of nano-TiO2 over the temperature range (293-373 K) at pH 3.0 and 7.25, using temperature scanning spectroscopy. In presence of nani-TiO2, the ester lytic activity of trypsin is decreased. The result indicates that Nano-TiO2 is a non-competitive inhibitor for enzyme trypsin. With the addition of TiO2 to protein solution at pH 3.0, the maximum intensity of emission spectrum of trypsin is increased. But at pH 7.25, the maximum intensity of emission spectrum of trypsin is decreased. The result of fluorescence spectroscopy indicated that the structure of the Trp residue environments was altered. Increasing the concentration of nano-TiO2 decreases the stability of trypsin to thermal denaturation.

Biosynthesis of metal nanoparticles using plant extract has received much attention due to its eco-friendly nature. The present study elucidates the green synthesize of Silver nanoparticles (AgNPs) from methanolic extract of Coleus Vettiveroids –an endemic species. The synthesis of AgNPs was confirmed by UV-visible spectrometry at 416 nm. Further, biosynthesized nanoparticles were characterized by FTIR for the confirmation of biomolecules acting as reducing agent. Average size and presence of elemental silver were characterized by scanning electron microscopy (SEM) and Transmission electron microscopy (TEM).Average size of nanoparticles was found to be 5 nm. The antioxidant ability of AgNPs was analyzed using DPPH. In vitro antibacterial effect of various concentrations of AgNPs was investigated against both Gram positive (S.Aureus) and Gram negative (E.Coli) bacterial strains. The result shows that biosynthesized AgNPs have significant antibacterial activity. Synthesized silver nanoparticles were also used effectively as photo catalyst in degradation of Organic Dyes and can be concluded that synthesized silver nanoparticles are also promising photo catalyst.

In this study, ion exchange nanocomposite membranes was prepared by addition of Mg(OH)2 nanoparticles to a blend containing sulfonated polyphenylene oxide and sulfonated polyvinylchloride via a simple casting method. Magnesium hydroxide nanoparticles were synthesized via a facile sono-chemical reaction and were selected as filler additive in fabrication of ion exchange nanocomposite membranes. Nanoparticles and nanocomposites were then characterized using scanning electron microscopy, Fourier transform infrared spectroscopy and X-ray diffraction. The effect of nanoparticles loading on physicochemical and electrochemical properties of prepared cation exchange nanocomposite membranes was studied. The membranes performance was evaluated by membrane potential, transport number, permselectivity, ionic permeability, flux of ions and membrane oxidative stability. Various characterizations revealed that the addition of different amounts of inorganic fillers could affect the membrane performance. The inorganic nanoparticles not only created extra pores and water channels that led to ion conductivity enhancement, but also improved transport number, permselectivity and flux of ions.

In the present research, the D-()-Glucose–confined water nanodroplets with mean size in the range of 6-11 nm were synthesized at D-()-Glucose different concentrations by AOT reverse micelles (RMs) method as a function of mass fraction of droplet (MFD) at the constant water-to-surfactant molar ratio ( W=40). The dynamic light scattering of the nano-sized water droplets containing the D-()-Glucose monosaccharide showed that interaction between the nanometer-sized AOT droplets changed from attractive to repulsive as the hydrophilic D-()-Glucose concentration increased as a function of MFD. The hydrodynamic diameter of water droplets increased as concentration of D-()-Glucose monosaccharide decreased in the water-in-oil AOT microemulsion.

In this study, the synthesis, characterization and controlled release behavior of new Hollow Silica Nano particles (HSNPs) and Magnetic Silica Nano Particles (MSNPs) were studied. Magnetic Silica Nano particles (MSNPs), as drug delivery vehicles, were synthesized through the coating of Fe3O4 nano-crystals with silica layers. The HSNPs were obtained by removal of Fe3O4 templates with hydrochloric acid and then calcinated at the high temperature. In the first step, MSNPs and HSNPs were modified and the amine and aldehyde functional groups were introduced on the silica surfaces. In the next step, positively charged silica nano particles were synthesized through the quaternization of Aminated Silica Nano Particles (ASNP) with sodium monochloroacetate (SMCA). Following characterization, insulin was loaded into the nano particles as a model system which demonstrated a notable sustained drug release. The study shows that the HSNPs could load a higher amount of drug. The release rates from the HSNPs were faster than those of MSNPs.

Low turn-on field of 2.3 V/µm was found for the emission current density of 10 µA/cm2 from 2D porous ZnO nanosheets. High current density of 0.76 mA/cm2 was drawn at an applied field of 4.1 V/µm. The observed low turn-on field of porous ZnO nanosheets has been found to be superior to the other ZnO nanostructures reported in the literature. Also, the emission current stability over a period of 3 hr is found to be better. The field emission current density-applied field (J-E) and current-time (I-t) measurements were carried out in all metal field emission microscope by using ‘close proximity’ (also termed as ‘planar diode’). The porous ZnO nanosheets were synthesized by Chemical Bath Deposition (CBD) method at room temperature followed by annealing at 200 oC. The annealed ZnO nanosheets were subjected to structural and morphological analysis prior to the field emission studies. The XRD spectrum of the as-synthesized product reveals formation of crystalline hexagonal phase of ZnO. Simple synthesis route with superior field emission properties indicate the possible use of porous ZnO nanosheets for micro/nanoelectronic devices.