Asian Journal of Nanoscience and Materials
Volume:3 Issue: 3, Jul 2020

In this work, the synthesis of iron oxide nanoparticles (NPs) was done by the extract of Ramalina sinensis. Co-precipitation method was usedto synthesize the nano-particles, which is very fast, low cost, and eco-friendly. For the green synthesis of the iron oxide nanoparticles, the distilled extract of Ramalina sinensiswas utilized. Also, to confirm the synthesis of the nanoparticles, some techniques such as UV-Vis spectrophotometry, XRD, FT-IR, and FESEMEDX were used. In addition the antimicrobial activity of biosynthetic magnetite nanoparticles against bacterial strainswas evaluated. The uniform spherical nature of the iron oxide nanoparticles with the particle size 31.74 to 53.91 nm was observed in the FESEM images. In the spectrum obtained from the spectrophotometer, the peak at 310±5 nm indicated the electron transfer from oxygen to the iron. The iron oxide NPs depicted effective antibacterial probably against Gram-positive bacteria Staphylococcus aureusand Gram-negative bacteria Pseudomonas aeruginosa. Based on the obtained results, it can be stated that the powerful approach of green synthesis of magnetic iron oxide NPs using Ramalina sinensis has led to producingthe nanoparticles with high antimicrobial potential.

This study used chitosan as a capping agent and L-ascorbic acid as reducing agent to prepare copper nanoparticles encapsulated with 2,4-D dimethylamine herbicide via a green chemical reduction method to improve its herbicidal activity and reduce the negative environmental impacts associated with its application. Characterization of the synthesized CuCtsNPs and 2,4-D-CuCtsNPs was carried out using the following techniques; transmission electron microscopy (TEM), fourier transform- infra-red (FT-IR), scanning electron microscopy (SEM), energy-dispersive x-ray (EDX), powder x-ray diffraction (PXRD), differential scanning calorimeter (DSC), thermogravimetric  and differential thermal analysis (TGA/DTA). The maximum absorption peak of CuCtsNPs was observed around 560 nm while that of 2,4-D-CuCtsNPs at 558 nm. The yield of CuCtsNPs was at the range of 40-92% and encapsulation efficiency of the 2,4-D-CuCtsNPs formulationwas 93%. Debye- Scherer’s equation was used to calculate the average crystalline size of the synthesized CuCtsNPs and 2,4-D-CuCtsNPs. The values were 38.78 nm (CuCtsNPs) and 54.93 nm (2,4-D-CuCtsNPs) respectively. The SEM images revealed the particle size of 21-56 nm for CuCtsNPs and 25-69 nm for 2,4-D-CuCtsNPs. The results obtained from the DSC and TGA curves of CuCtsNPs and 2,4-D-CuCtsNPs showed that the formulations exist in crystalline state and were thermally stable up to 401.73 °C. Aqueous release studies for the formulation were carried out in three different pH media and two agricultural soils. Leaching profile of the loaded CuCtsNPs through the soil layer (UAM and CAPS) demonstrated that the UAM soil had higher value for 2,4-D (58.67%) than in CAPS soil 40.78%. This study formulated an environmentally friendly herbicide delivery nano-matrix (CuCtsNPs) for the successful slow release of 2,4-D Dimethylamine herbicide in aqueous medium and agricultural soils.

In this research study, the growth of SnZnSe thin film materials was carried out using the cationic precursor, which was an aqueous solution of 0.035 mol solution of ZnSO4.7H2O while the anionic precursor was 0.1 mol solution of selenium metal powder was prepared by dissolving with 4 mL of hydrogen chloride (HCl). The XRD of the films deposited on FTO substrates at different dopant concentration 1%, 2%, 3% and 4% showed the reflection peaks at (220), (221), (300), (310), (311), (222) and (320) with the lattice constant of a=7.189 Ǻ.  The SEM results revealed the random distribution of tiny nano-grains on the substrate, the nano-grains were observed to agglomerate due to the presence of large free energy characteristics of small particles. The optical bandgap of the deposited material enhanced from 2.0-2.3 eV as the dopant concentration increased.

In this study, graphene oxide was functionalized with 3-aminopyridine to prepare a novel nanocatalyst known as the graphene oxide functionalized pyridine-methanesulfonate (GO@PyH-CH3SO3). The GO@PyH-CH3SO3 was then employed as an effective nanocatalyst to prepare 4, 4'-(aryl methylene)-bis(1H-pyrazol-5-ols) via one-pot multicomponent condensation reaction of aldehydes with 3-methyl-1-phenyl-1H-pyrazol-5(4H)-one. The best reaction condition involved the use of 0.02 g of the catalyst for 20 min and at 70 °C without using any solvent. Also, the reusability of catalyst and product yield in five runs was examined and no significant change was observed. The leaching test was utilized to assess the nature of the catalytic activity, and the results showed the heterogeneous condition for the catalytic activity. Efficiently and capability of the GO@PyH-CH3SO3 catalyst and other catalysts were compared and showed the superior properties of this catalyst.

Composite materials play a vital role in present industrial applications due to their positive properties when compared with the existing or conventional materials used for the same applications such as weight, strength, and flexibility in design. In this work, a laminate was prepared by considering three different fibers including, basalt, carbon, and glass fiber. The order of orientation is three different forms 40°, 60°, and 90°. The stacking of the fibers is of the same degrees and it is subjected to two different sets of tests such as failure analysis and thermal analysis. The results revealed that, increasing basalt fiber content (up to 50% wt.) reduced the thermal conductivity of the composite while reducing the glass fiber content increased the thermal conductivity. In addition, the orientation of 90o showed the best tensile strength and elongation over 40o and 60o.

Graphene based nanocomposites have been used to improve the osteogenic differentiation of stem cells. In this research study, the reduced graphene oxide (rGO) sheets were used as the base material while decorated with strontium doped hydroxyapatite (rGO/HAP/Sr). X-ray differentiation (XRD) analysis and transmission electron microscopy (TEM) were employed to evaluate the size and morphology of the HAP/Sr decorated rGO. Fourier transform infrared (FT-IR) was used to analyze the nanocomposites’functional groups.Raman spectroscopy was used to investigate the possible disorders in rGO/HAP/Sr structure and the number of layers. Ion-coupled plasma optical emission spectroscopy (ICP-OES) was used for evaluating the atomic concentrations of the elements (Ca and Sr) in nanocomposites. Likewise, zeta potential of thenanocomposite was determined to be -18.9 mV. To evaluate the cytotoxicity of the nanocomposites, MTT assay was performed. The osteo-inductive potential of the synthesized rGO/HAP/Sr nanocomposites was investigated using the adipose-derived mesenchymal stem cells (ADCs). Osteogenic differentiation was confirmed by measuring the calcium content. The results revealed that the nanocomposites concentrations induce calcium deposition by cells, indicating that the bone differentiation was done successfully. Lastly, it can be concluded that, this nanocomposite, alone, can be used for bone differentiation induction without using any chemical inducers.

In this research study, one-pot, four-component reaction of 3-aryl-3-oxopropanenitriles, 1-aryl-3-methyl-1H-pyrazol-5 (4H) one, arylglyoxals and ammonium acetate using green solvent systems and different catalysts under the reflux conditions afforded a series of the corresponding 4-aroyl-3-methyl-1,6-diaryl-1H-pyrazolo [3,4-b] pyridine-5-carbonitrile derivatives. The best yields (70-85%) were obtained using the metal oxide silica based-matal bifunctional LDH (layered double hydroxide) as a magnet nanocatalyst in EtOH/H2O (1:1) under the reflux conditions. This protocol provided mild reaction conditions, good yields, simple workup procedure, easy preparation of nanocatalyst and, products to structurally diverse bicyclic pyrazolo [3,4-b] pyridines, demonstrating biological and pharmacological activities.

Quickly developing industrialization is one of the significant benefactors of natural contamination as it presents awful difficulties for the earth and the ordinary citizens. Biological synthesis of the silver nanoparticles (AgNPs) atthe presence of the aqueous leaf extract of Celosia argentea, funtioned as the reducing and capping agent. In this research study, we are reportthe synthesis of the AgNPs with the optimized experimental parameters at the pH. Formation of the AgNPs was confirmed by the UV-Visible spectroscopy and FT-IR analysis. The structural characterization was carried using the SEM-EDX, providing the size of the nanoparticles to be 50-80 nm. The AFM showed the spherical surface topology, the zeta potential whereas, particle size analysis showed stability and the average size was determined to be 50 nm.