Current Nanomaterials - Volume 8, Issue 2, 2023

Nanomaterials (NMs) particularly synthesized by green routes have attracted researchers and scientists for their multifunctional industrial applications. NMs have not only revolutionized research, but also our daily life because of numerous applications in medical diagnostics, consumer products, and energy-related applications. Their unique properties are directly related to chemical composition, structure, size and shape. There are several characterization techniques used to determine the size, composition, crystalline structure and other physical properties of NMs. Prominent among them are spectroscopic techniques such as UV-Visible, FTIR, EDX; diffraction techniques such as XRD, SAED; microscopic techniques such as SEM, TEM, AFM and others such as Zeta potential measurements. Every technique has its own merit and demerit. This mini review describes the uses of UV-Vis spectroscopy in characterization of NMs.

In recent years, the green synthesis of different metal nanoparticles has become a substantial technique for the synthesis of different essential nanoparticles and their potential applications in technological, industrial along with biomedical fields. Among the several essential nanoparticles, copper nanoparticles (CuNPs) have attracted enormous attention for their wide range of applications like the production of gas sensors, solar cells, high-temperature superconductors as well as drug delivery materials and catalysis owing to its distinctive optical, electrical, dielectric, imaging and catalytic, etc. properties. Herein, in this review, our aim is to find out the recent progress of synthesis, as well as different optical and structural characterizations of green, synthesized CuNPs along with their broadspectrum biomedical applications, mainly antibacterial, antifungal, antiviral and anticancer as well as the future perspective of research trends in the green synthesis of CuNPs. CuNPs have been synthesized by different researchers using three methods, namely, physical, chemical, and biological. In this review, the eco-friendly, efficient and low cost different established biological/green synthesis methods of CuNPs using different plant extracts like leaves, flowers, fruits, seeds, latex, etc., as capping and reducing agents have been briefly discussed, along with reaction conditions together with their optical as well as structural analysis. Effects of different parameters on the green synthesis of CuNPs like the presence of phytochemicals and confirmation of phytochemicals, temperature, pH, etc., are elucidated. Studies of the antibacterial activity of biomolecules capped CuNPs by different researchers against both Gram-positive and Gram-negative bacterial strains along with minimum inhibitory concentration (MIC) values have been summarized. Furthermore, antifungal and antiviral effects of green synthesized CuNPs studied by different researchers are mentioned with minimum inhibitory concentration (MIC) values. The anticancer activity of green synthesized CuNPs against different cancer cells studied by different researchers is summarized with correlation sizes of CuNPs on anticancer activity. The review also focuses on in vivo applications of green synthesized CuNPs along with clinical trails. Furthermore, an emphasis is given to the effectiveness of CuNPs in combating COVID-19.

Lipid nanocarriers are reaching new heights in the field of drug delivery. The core of this technology resides in simple molecules, i.e., lipids. Solid and liquid lipids of biocompatible and generally recognized as safe (GRAS) status are employed for the development of lipid nanoparticles along with surfactant(s), solvents, and drug molecules. Researchers have practiced a variety of solid and liquid lipids with acceptable profiles in the formulation of lipid nanoparticles. Solid lipids like triglycerides, fatty acids, fatty alcohols, waxes, and butter have been used in designing lipid nanocarriers. The potential of various plant-based oils has also been tested in designing nanostructured lipid carriers (NLC). With the exponential advancement in lipid-based delivery systems, there exists a need for an appropriate lipid system to obtain an effective product. This review gives a brief insight into lipids, which have been exploited by researchers for designing solid lipid nanoparticles (SLN) and nanostructured lipid carriers. A tabular presentation of important key points of past studies exploiting these lipids for preparing SLN/NLC is the highlight of the article.

Aim: The aim of this study was to develop and characterize Methotrexate loaded solid lipid nanoparticles by Microemulsion technique. Background: Methotrexate is a preferable anti metabolite drug. It is used in the treatment of certain cancers like breast cancer, skin and lung cancer. Clinical studies have revealed that the curative effect of MTX tablet on cancers was limited due to their toxic dose-related side effects to normal cells, nephrotoxicity, and bone marrow suppression, acute and chronic hepatotoxicity and also due to the drug resistance of the tumour cells. Hence, there is a need to develop methotrexate solid lipid nanoparticles in order to minimize the adverse effects associated with the MTX tablet dosage form. Objectives: The objective of the research work is to formulate, characterize and evaluate Methotrexate solid lipid nanoparticles by micro emulsification solidification technique. Methods: Solid lipid nanoparticles are prepared by using lipids stearic acid and glycerol monostearate by varying the concentration of surfactant. Three formulations were prepared with each lipid. Micro emulsion technique was adopted for the preparation of solid lipid nanoparticles. Each formulation was evaluated for drug content, entrapment efficiency, loading capacity and in vitro drug release studies. Both the lipids were compared for the characterization and evaluation parameters. Results: On comparison Glycerol monostearate was found to be a better lipid over Stearic acid for the preparation of Methotrexate solid lipid nanoparticles because of its smaller mean particle diameter (238.8 nm), higher stability (-56.5 mV) and greater entrapment efficiency. Conclusion: Methotrexate solid lipid nanoparticles were successfully prepared with higher stability and drug release rate.

Aims: This study aimed to evaluate the mechanical properties of polymer nanocomposites (PNCs) reinforced with multi-walled carbon nanotubes (MWCNT). Methods: Mixing MWCNT into the polymer at very small propositions can enrich the mechanical properties of the polymer nanocomposites. The test specimen was fabricated with 0.1wt%, 0.5wt%, and 1wt% mixing ratios using extrusion and injection molding process. Computational analysis was performed through the square RVE model and analyzed with finite element analysis (FEA) using the DIGIMAT simulation tool. The specimens were evaluated by ASTM D3039 for tensile strength and ASTM D7264 for flexural strength. Results: The simulated results were compared with experimental results. Scanning electron microscopy( SEM) was performed to evaluate the dispersion state of nanotubes in the matrix. Conclusion: The impactful improvement in mechanical properties has been observed after adding functionalized MWCNTs (f-MWCNT) compared to pure polymer and non-functionalized MWCNT composites.

Introduction: Zinc oxide nanoparticles belong to the new age of nanomaterials; they are being used tremendously for the advancements of biomedicine and modern therapeutic interventions. Purpose: The current antimicrobial treatment methods fail on various levels. Thus, the recent study is dedicated to synthesizing stable zinc oxide nanoparticles. Therefore, the application of zinc oxide nanoparticles as an alternative treatment option is explored. Methods: In the current research, fabrication of zinc oxide nanoparticles is carried out via the wet chemical method. To further confirm the purity and stability of the synthesized material, characterization was performed via zeta potential analysis, thermogravimetric analysis, differential scanning calorimetry, transmission electron microscopy and scanning electron microscopy. Results: SEM and TEM revealed the spherical structure of zinc oxide nanoparticles, also having slight agglomeration at a few points. The thermal stability was tested via thermogravimetric analysis and differential Scanning Calorimetry depicting the strength of the nanomaterial at a very high temperature. Elemental composition was evaluated using Energy Dispersive X-ray Spectroscopy showing 96.01% zinc and 3.99% oxygen, demonstrating the purity of the synthesized zinc oxide nanoparticles. It confirms that no other elements are present apart from zinc and oxygen. Conclusion: Zinc oxide nanoparticles were synthesized via a wet chemical method using zinc nitrate and sodium hydroxide. This fabrication procedure is reliable, cheap, and yields the most stable byproducts. Characterization was carried out via several analytical techniques to check the authenticity of the synthesized nanomaterial, thus revealing that the obtained ZnO nanoparticles could be used in medical interventions as a safe option.

Aims: The aim of this study is to evaluate the photocatalytic degradation of methylene blue dye on cuprous oxide/graphene nanocomposite. Background: Cuprous oxide (Cu2O) nanoparticles are among the metal oxides that demonstrated photocatalytic activity. However, the stability of Cu2O nanoparticles due to the fast recombination rate of electron/hole pairs remains a significant challenge in their photocatalytic applications. This in turn, leads to mismatching of the effective bandgap separation, tending to reduce the photocatalytic activity of the desired organic waste (MB). To overcome these limitations, graphene has been added to make nanocomposites with cuprous oxides. Objective: In this study, Cu2O/graphene nanocomposite was synthesized and evaluated for its photocatalytic performance of Methylene Blue (MB) dye degradation. Method: Cu2O/graphene nanocomposites were synthesized from graphite powder and copper nitrate using facile sol-gel method. Batch experiments have been conducted to assess the applications of the nanocomposites for MB degradation. Parameters such as contact time, catalyst dosage, and pH of the solution were optimized for maximum MB degradation. The prepared nanocomposites were characterized by using UV-Vis, FTIR, XRD, and SEM. The photocatalytic performance of Cu2O/graphene nanocomposites was compared against Cu2O nanoparticles for cationic MB dye degradation. Results: Cu2O/graphene nanocomposite exhibits higher photocatalytic activity for MB degradation (with a degradation efficiency of 94%) than pure Cu2O nanoparticle (67%). This has been accomplished after 180 min of irradiation under visible light. The kinetics of MB degradation by Cu2O/graphene composites can be demonstrated by the second-order kinetic model. The synthesized nanocomposite can be used for more than three cycles of phtocatalytic MB degradation. Conclusion: This work indicated new insights into Cu2O/graphene nanocomposite as highperformance in photocatalysis to degrade MB, playing a great role in environmental protection in relation to MB dye.

Background: We have studied the Coulomb drag phenomena for hole-hole static potentials theoretically and measured numerically using the random phase approximation (RPA) method. Objective: The drag resistivity is evaluated at low temperature, large interlayer separation limit and weakly screening regime, with the geometry of two atomically thin materials, such as BLG/GaAsbased multilayer system, which is a promising system in nanomaterials and technology. Methods: Static local field corrections (LFC) are considered to take into account the Exchangecorrelations (XC) and mutual interaction effects with varying concentrations of the active and passive layer. Results: It has been found that the drag resistivity gets enhanced on using the LFC effects and increases on increasing the effective mass. In Fermi-Liquid regime, drag resistivity is directly proportional to T², n^-3, d^-4 and ε² with respect to temperature (T), density (n), interlayer separation (d∼nm) and dielectric constant (ε2), respectively. Conclusion: Dependency of drag resistivity is measured and compared to 2D e-e and e-h coupledlayer systems with and without the effect of non-homogeneous dielectric medium.