Investigation of structural, morphological, optical, elemental, and anticancer property of pure ZnO and PbO: ZnO nanocomposites prepared by flame synthesis method.

In this work, Pure ZnO nanoparticles and a nanocomposite of PbO: ZnO were prepared by the flame synthesis method, and was analyzed for structural, morphological, optical, elemental, and biocompatibility studies. The structural analysis revealed a hexagonal structure for ZnO and an Orthorhombic structure for PbO: ZnO nanocomposite. Scanning electron microscopy (SEM) image showed a Nano-Sponge-like surface morphology for PbO: ZnO nanocomposite and energy dispersive spectra (EDS) confirmed the absence of undesired impurities. Transmission electron microscopy (TEM) image showed a particle size of ∼50 nm for ZnO and ∼20 nm for PbO: ZnO. Using Tauc plot the optical band gap was found to be 3.2 eV for ZnO and 2.9 eV for PbO: ZnO. Anticancer studies confirm the excellent cytotoxicity activity of both compounds. PbO: ZnO nanocomposite has demonstrated the highest cytotoxicity against the tumorigenic HEK 293 cell line with the lowest IC50 value of 13.04 µM. Our study shows that the prepared PbO: ZnO nanocomposite has a huge potential in cancer therapy.

Progress and Prospects on the Fabrication of Graphene-Based Nanostructures for Energy Storage, Energy Conversion and Biomedical Applications.

Graphene, a two-dimensional (2D) layered material has attracted much attention from the scientific community due to its exceptional electrical, thermal, mechanical, biological and optical properties. Hence, numerous applications utilizing graphene-based materials could be conceived in next-generation electronics, chemical and biological sensing, energy conversion and storage, and beyond. The interaction between graphene surfaces with other materials plays a vital role in influencing its properties than other bulk materials. In this review, we outline the recent progress in the production of graphene and related 2D materials, and their uses in energy conversion (solar cells, fuel cells), energy storage (batteries, supercapacitors) and biomedical applications.

Recent Progress and Perspectives on Electrochemical Regeneration of Reduced Nicotinamide Adenine Dinucleotide (NADH).

NAD is a cofactor that maintains cellular redox homeostasis and has immense industrial and biological significance. It acts as an enzymatic mediator in several biocatalytic electrochemical reactions and undergoes oxidation/reduction to form NAD+ or NADH, respectively. The NAD redox couple (NAD+ /NADH) mostly exists in enzyme-assisted metabolic reactions as a coenzyme during which electrons and protons are transferred. NADH shuttles these charges between the enzyme and the substrate. In order to understand such complex metabolic reactions, it is vital to study the bio-electrochemistry of NADH. In addition, the regeneration of NADH in industries has attracted significant attention due to its vast usage and high cost. To make biocatalysis economically viable, primary methods of NADH regeneration including enzymatic, chemical, photochemical and electrochemical methods are widely used. This review is mainly focused on the electrochemical reduction of NAD+ to NADH with specific details on the mechanism and kinetics of the reaction. It provides emphasis on the different routes (direct and mediated) to electrochemically regenerate NADH from NAD+ highlighting the NAD dimer formation. Also, it describes the electrocatalysts developed until now and the scope for development in this area of research.

Development of colorimetric cholesterol detection kit using TPU nanofibre/cellulose acetate membrane.

In this study, the authors report a simple fabrication of thermoplastic polyurethane (TPU) nanofibres-based kit for cholesterol detection. TPU is a polymer that is highly elastic, resistant to microorganisms, abrasion and compatible with blood; thus, making it a natural selection as an immobilisation matrix for cholesterol oxidase (ChOx) enzyme. The nanofibre was fabricated by electrospinning process and was characterised using scanning electron microscopy and Fourier transform-infrared spectroscopy. ChOx was covalently immobilised on TPU nanofibre and cholesterol level/concentration was visually found using 4-aminoantipyrine, a dye that reacts with H2O2 produced from the oxidation of cholesterol by ChOx and changes colour from yellow to red. The efficacy of the nanofibre to act as a detecting substrate was compared with cellulose acetate (CA) membrane, a well-documented enzyme immobilisation matrix. The optimisation of enzyme concentration and dye quantity were performed using standard ChOx spectrophotometric assay and the same was used in CA membrane and TPU nanofibre. The ChOx immobilised nanofibre showed good linear range from 2 to 10 mM with a lower detection limit of 2 mM and was highly stable compared to that of CA membrane. The enzyme immobilised nanofibre was further validated in serum samples.