Nanoscience & Nanotechnology-Asia - Volume 10, Issue 2, 2020

In recent time, green synthesis of Metal Nanoparticles (MNPs) is the latest developing technology and received exceptional interest because it is simple, eco-friendly, pollutant-free, nontoxic, and a low-cost approach. Green route of biogenic synthesis of metal nanoparticles via microbes (bacteria, fungi, virus, yeast, algae etc.) has the potential to deliver clean manufacturing technology. Fungi are in the great use for the synthesis of nanoparticles and are more advantageous as compared with other microorganisms in several ways. Fungi grow in the form of a group of mycelia, which helps them to withstand flow pressure and agitation and various other conditions to which microbes are subjected to in a bioreactor, used for large-scale production. This review has its major focus on fungus Fusarium oxysporum, which is capable of synthesizing a large number of different types of nanoparticles such as titanium, magnesium, platinum, silver, gold, zirconium, and strontium, titania and silica oxide and many more. Biogenically synthesized nanoparticles are characterized by different techniques and exhibited biological activity. The fungi with metabolic capabilities can effectively synthesize a large number of nanoparticles both extracellularly and intracellularly. The biologically synthesized nanoparticles have wide ranges of applications especially in agricultural and medicinal industries.

Deformation twins and phase interface are important planar defects and microstructures that greatly influence the overall performance of a material system. In multi-layer thin-film heterostructures, their effect is more manifest due to the small dimension of thin films and their influence on the growth of multi-layer structures. This article reviews the recent progress in microstructure and defects observed in thin film heterostructures, serving as a guideline for future research in this field. The multilayer thin-film heterostructures studied here were grown by pulsed laser deposition technique. Microstructures and defects were investigated by Transmission Electron Microscopy.

Aim: The purpose of this study was to test the phytotoxicity effect of ZnONPs on Vigna mungo L. seedling growth and antioxidant activity. Methods: Vigna mungo L. Seeds were treated with to a wide range of ZnO NPs ranging 5 to25mg/100ml for 8hours. Vigna mungo seeds that were soaked in ZnO NPs solution were sown in pots (20 cm × 40 cm) filled with red soil and a layer of coco peat. The effect of ZnO NPs on morphological, biochemical and antioxidant activity in Vigna mungo L. plants was investigated after 15,30,45 and 60 days. Results: The impact of ZnO NPs on plant growth characteristics and biochemical changes in Vigna mungo L. plants was investigated after 15,30,45 and 60 days. The ZnONPs exposure significantly enhanced germination percentage by 111.3% but root length (75.25%), shoot length (89.81%), number of leaves (91.66%), length of leaves (76%), width of leaves (67.27%), fresh weight of plant (27.96%) and dry weight of plant (28.23%) decreased in the treated plants after 60 days exposure to 25mg/100ml compared to the untreated control. Interestingly, treated plants after 60 days exposure to 25mg/100ml increased significantly the chlorophyll (115.0%), reducing sugars (244.4%), total sugars (212.72%) protein (181.8%). Treatment to Vigna mungo L. seeds with ZnONPs has been found to induce the activities of antioxidant enzymes such as Guaiacol peroxidase, Glutathione Reductase, Catalase and increase in the ascorbic acid and hydrogen peroxide contents. TEM images revealed that the aggregated ZnO NPs to be deposited inside the seed. Conclusion: Vigna mungo seeds treated with different concentrations of ZnO NPs showed decreased root growth and increased germination index, shoot and leaf growth. There was a significant change in Glutathione reductase, Guaiacol peroxidase and Catalase activity and ascorbic acid and hydrogen peroxide of Vigna mungo exposed to ZnONPs. Aggregated nanoparticles penetration into the intracellular region of the seed was observed.A complete study on the toxic effects of ZnO NPs can help significantly in the safe disposal of ENPs for the reduction of adverse effects in both environmental and agricultural systems.

Background: Iron oxide (γ-Fe2O3) nanoparticles have been prepared by a simplified coprecipitation method. Methods: X-ray diffraction peaks of the prepared nanoparticles match well with the characteristic peaks of crystalline g-Fe2O3 as per JCPDS data (JCPDS Card No. 39-1346) and absorption peak at 369 nm along with band gap 2.10 eV suggesting the formation of (γ-Fe2O3) nanoparticles. Results: The γ-Fe2O3 nanoparticles are spherical in nature with a diameter around ~10 nm. Conclusion: The crystalline g-Fe2O3 nanoparticles exhibit excellent super-paramagnetic behavior not only at room temperature (300K) but also at a temperature as low as 100K.

Background: This research indicated that such abstract are more informative and more readable, in field of preparation of nanocomposite materials. Aim: The purpose of this work represented by decoration of Carbon Nanotubes (CNTs) with nanoparticles using co-precipitation method and exhibit different physical properties from those of CNTs alone and its appropriate for this particular journal. Methods: Preparation MWCNTs surface by Ag/ZnO nanoparticles using two steps represented by acid treatment of MWCNTs in a mixture acid of sulfuric acid (95% H2SO4) and nitric acid (65% HNO3) at 3:1 ratio and second step represented by decoration of Ag/ZnO nanoparticles on FMWCNTs using co-precipitation method to prepare ZnO/Ag nanoparticles decorated on F-MWCNTs as nanocomposite material. Results: The results of this work reveal the decoration of Ag-doped ZnO nanoparticles on the FMWCNTs was achieved without any impurities as shown in XRD, Raman spectra and FTIR and FESEM observations reveal that Ag-doped ZnO nanoparticles have spherical morphologies and adhered on the functionalized MWCNTs, with diameters are about 22-30 nm. Also it is clear that there were no any other materials on the surface of F-MWCNTs except ZnO and Ag which verifies the results obtained from XRD and EDS analysis. Conclusion: In this article, Ag-doped ZnO nanoparticles have been successfully decorated on to modified MWCNTs by an in-situ co-precipitation method. From XRD results, it can be seen that the (002) peak of MWCNTs slightly increased after the addition of Ag-doped ZnO nanoparticles. Raman spectra and FTIR analysis confirmed the formation of Zn-C or Zn-O-C bonds between acid-treated MWCNTs and Ag-doped zinc oxide. The FESEM and EDS analysis revealed that the decoration of Ag-doped ZnO nanoparticles on the F-MWCNTs was achieved without any impurities. Finally, the small sizes Agdoped ZnO NPs deposited on F-MWCNTs make it very promising for biomedicine applications.

Background: Electrospinning is a novel cost effective technique for generating nanofibers from a broad range of materials likely to be used as a coating film. Methods: In this project, pectin and chitosan solutions containing PVA were prepared and electrospun with separate syringes for the first time. The antimicrobial and physical properties of the novel chitosan/PVApectin/ PVA nanofibrous film were evaluated using some analysis techniques such as disc diffusion assay, scanning electron microscopy (SEM), transmission electron microscopy (TEM), viscosity and conductivity tests, and fourier-transform infrared spectroscopy (FTIR). Results: The results showed that simultaneously electrospinning the dispersion of chitosan/PVA (50:50) with pectin/PVA (50:50) led to the formation of thin nanofibers with the minimum number of beads. The results of FTIR analysis proved the dispersion of chitosan and PVA in nanofiber mats and the interaction of chitosan with pectin as well as PVA with pectin. Disc diffusion assay showed that nano-film could possess significant antibacterial activity against S. aureus at 37°C but had no effects against E. coli. Conclusion: Based on the results of this study, the novel chitosan/PVA-pectin/PVA nanofibrous film can be considered as a novel coating film for promising application in food packaging industry.

Introduction: This paper proposes an approach for parameter estimation of the Classical and Generalized Morse Potential functions. A new potential which is a modification of the Generalized Morse Potential was proposed as parameter estimates yielded complex conjugate roots using gold atom for simulation. Methods: Existing methods of parameter estimation requires the provision of initial guess values of which convergence to the optimal solution is not always guaranteed. This makes provision of initial guess values that guarantees convergence to the optimum solution more of an art than a science. The proposed objective least squares function method does not require the provision of initial guess values and it involves the minimization of two formulated objective functions using the differential numerical approach and least squares method. The built-in “Minimize” function of Mathematica® is also used to minimize the formulated objective function. Potential energy curves were constructed by fitting estimated parameter values to experimental data sets of the gold atom using values of the proposed approach and Mathematica® for performance evaluation. Errors of each constructed potential energy curves were simulated. Results: It was observed that the errors were very small for both the Classical and Modified Generalized Morse Potential. Conclusion: Hence the approximations of the proposed approach are very good.

Background: Rare earth materials are known for its salient electrical insulation properties with high values of electrical resistivity. It is expected that the substitution of rare earth ions into spinel ferrites could significantly alter its magnetic properties. In this work, the effect of the addition of Samarium ions on the structural, morphological and magnetic properties of Ni0.5Zn0.5SmxFe2-xO4 (x=0.00, 0.02, 0.04, 0.06, 0.08, 0.10) synthesized using sol-gel auto combustion technique was investigated. Methods: A series of Samarium-substituted Ni-Zn ferrite nanoparticles (Ni0.5Zn0.5SmxFe2-xO4 where x=0.00, 0.02, 0.04, 0.06, 0.08, 0.10) were synthesized by sol-gel auto-combustion technique. Structural, morphological and magnetic properties of the samples were examined through X-Ray Diffraction (XRD), Field-Emission Scanning Electron Microscope (FESEM) and Vibrating Sample Magnetometer (VSM) measurements. Results: XRD patterns revealed single-phased samples with spinel cubic structure up to x= 0.04. The average crystallite size of the samples varied in the range of 41.8 – 85.6 nm. The prepared samples exhibited agglomerated particles with larger grain size observed in Sm-substituted Ni-Zn ferrite as compared to the unsubstituted sample. The prepared samples exhibited typical soft magnetic behavior as evidenced by the small coercivity field. The magnetic saturation, Ms values decreased as the Sm3+ concentration increases. Conclusion: The substituted Ni-Zn ferrites form agglomerated particles inching towards more uniform microstructure with each increase in Sm3+ substitution. The saturation magnetization of substituted samples decreases with the increase of samarium ion concentration. The decrease in saturation magnetization can be explained based on weak super exchange interaction between A and B sites. The difference in magnetic properties between the samples despite the slight difference in Sm3+ concentrations suggests that the properties of the NiZnFe2O4 can be ‘tuned’, depending on the present need, through the substitution of Fe3+ with rare earth ions.

Background: This work describes the implementation of In0.53Ga0.47As/InP Surrounding Metal Gate Oxide Semiconductor Heterostructure Field Effect Transistor (SG MOSHFET) with gate underlap on both source and drain end to improve the DC and RF performance. Methods: A comprehensive and methodological investigation of DC and RF performance of III-V semiconductor are made for different underlap length varying from 5nm to 30nm on both sides of the device, which is used to mitigate the short channel issues to improve the device performance. Hydrodynamic model has been taken into consideration for the device simulation and it also includes Auger recombination and the Shockley–Read–Hall (SRH) model. Simulation is performed to analyze the various analog performance of device like drain current, surface potential, transconductance, threshold voltage, drain induced barrier lowering, off current, subthreshold slope, Ion/Ioff ratio, output conductance, intrinsic delay, energy-delay product, transconductance generation factor and radio frequency performance of device, like trans-frequency product and cut-off frequency. Results: From the simulation, it can be observed that an improved analog and RF performance is obtained at the optimum underlap length. Conclusion: This work delivers an idea for extended researchers to investigate different aspects of group III–V underlap MOSFETs.

Background: Magnetic cell immobilization has been introduced as a novel, facile and highly efficient approach for cell separation. A stable attachment between bacterial cell wall with superparamagnetic iron oxide nanoparticles (SPIONs) would enable the microorganisms to be affected by an outer magnetic field. At high concentrations, SPIONs produce reactive oxygen species in cytoplasm, which induce apoptosis or necrosis in microorganisms. Choosing a proper surface coating could cover the defects and increase the efficiency. Methods: In this study, asparagine, APTES, lipo-amino acid and PEG surface modified SPIONs was synthesized by co-precipitation method and characterized by FTIR, TEM, VSM, XRD, DLS techniques. Then, their protective effects against four Gram-positive and Gram-negative bacterial strains including Enterococcus faecalis, Staphylococcus aureus, Escherichia coli and Pseudomonas aeruginosa were examined through microdilution broth and compared to naked SPION. Results: The evaluation of characterization results showed that functionalization of magnetic nanoparticles could change their MS value, size and surface charges. Also, the microbial analysis revealed that lipo-amino acid coated magnetic nanoparticles has the least adverse effect on microbial strain among tested SPIONs. Conclusion: This study showed lipo-amino acid could be considered as the most protective and even promotive surface coating, which is explained by its optimizing effect on cell penetration and negligible reductive effects on magnetic properties of SPIONs. lipo-amino acid coated magnetic nanoparticles could be used in microbial biotechnology and industrial microbiology.

Background: CdSe QDs, synthesized using a green micro-emulsion method, have been evaluated for their potential in inducing HL-60 differentiation by employing various biochemical assays and as cellular imaging agents. Methods: CdSe QDs have been found to effectively induce differentiation with lower rate of cell apoptosis as compared with the positive control (DMSO). Results: Our results exhibit effective induction of HL-60 differentiation by CdSe QDs implicating their therapeutic role in cancerous cells in addition to their usual application as cell-imaging agents. Conclusion: Our studies report that the chemo-preventive properties of CdSe exhibit great potential and further tailored-synthesis and cell-differen-tiations studies have a promising future in the preventive treatment of HL60 cancerous tissue.