Carbon quantum dots (CQDs) have a size of 10 nm (or less), with lots of biomedical advantages, creating huge excitement in different research fields. The aim of this study includes an eco-friendly synthesis of biogenic CQDs from grape (Vitis vinifera) seeds, identifying the characteristics and assessing its anti-diabetic as well as anti-microbial activity. CQDs are prepared by the pyrolysis method. Synthesized CQDs were confirmed by ultraviolet (UV)–visible (Vis) spectrophotometer, and the characterization study was done by X-ray diffractometer, photoluminescence spectroscopy, Fourier transform infra-red spectroscopy, and transmission electron microscopy with selected area electron diffraction (SAED). Anti-diabetic activity of CQDs was analyzed by in vitro α-glycosidase, α-amylase inhibition assays, and glucose uptake studies. The anti-bacterial activity of CQDs was analyzed by anti-microbial assay technique against Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus, and Streptococcus mutans. The results showed that the CQDs synthesized from a natural source like grape seeds, were amorphous in nature, the average particle size was 4 nm, and they contain functional groups like carboxyl and hydroxyl. Subsequently, it showed that the sp2 domains also produce green fluorescence. The anti-diabetic experimental method revealed that the CQDs enhance glucose uptake and inhibit carbohydrate hydrolyzing enzymes. CQDs also exhibit anti-bacterial properties against both Gram-positive and Gram-negative bacteria, according to their antimicrobial impact. Due to their small size and higher activity, CQDs will become strong anti-diabetic agents as well as anti-bacterial ones.

Exfoliation of graphene from graphite is one of the leading processes in the branch of nanotechnology, where surfactants are used as a unique solvent in combination with graphite and nitrogen gas atmosphere. This process would let the graphite to reduce into a monolayer in the presence of liquid phase with surfactants which have the equal surface energy to exfoliate graphene from graphite. There are many applications in nanotechnology for graphene flakes, but the production is costly as it is quite challenging to indulge graphite in the liquid phase. This review gives vast information about introducing a surfactant taken from various sources for exfoliating graphene flakes. It also provides a broad background regarding the isolation, production, and extraction of biosurfactants from organisms along with its role in nanotechnology.

A simple and reproducible biosynthetic method was employed to synthesize iron and silver nanoparticles which resulted in monodispersed nanoparticles of high concentration. The iron oxide nanoparticles has been widely favored because of low cytotoxicity, biodegradable and reactive surface that can be modified with biocompatible coatings. Silver nanoparticles have been a potent antibacterial, antifungal, anti-viral and antiinflammatory agent. The reaction process was simple, eco-friendly, inexpensive and easy to handle. Green and chemical methods were employed to synthesize iron and silver nanoparticles. A microbial route to synthesize iron and silver nanoparticles by the fungal strain Fusarium oxysporum sp. and Actinomycetes sp. was done simultaneously. Production of nanoparticles using fungi has some advantages over other organisms as it is easy to handle and require simple raw materials. The obtained iron and silver nanoparticles were characterized by UV-vis spectroscopy, Fourier transform infrared spectroscopy (FTIR) and the morphology of prepared nanoparticles was confirmed by Transmission electron microscopy (TEM). TEM images of Iron nanoparticles synthesized by Fusarium oxysporum sp. showed 20-40 nm sized particles. These particles exhibited maximum antibacterial activity against Bacillus, E. coli and Staphylococcus sps. TEM images of biosynthesized silver nanoparticles were of smaller size (10-20 nm). The microbially synthesized silver nanoparticles using Actinomycetes were found to be highly toxic against different human pathogens due to the smaller size and due to the presence of antibiotic components available on them. The mechanism of antimicrobial property of nanoparticle lies with the fact that the extremely small size means a large surface area relative to the volume, which effectively covers the microorganisms and reduce oxygen supply for respiration. It was found that silver nanoparticles synthesized by the microbial route have a greater antibacterial activity.

Prion diseases are associated with the accumulation in the brain of an abnormal, protease resistant isoform of a host encoded glycoprotein known as prion protein (PrP). Nanotechnology in combination with biotechniques promises a broad spectrum of highly innovative approaches for overcoming the challenges posed by the prions. Recent advances in molecular nanobiotechnology have brought in the potential of molecular targeting in diagnosis and therapies of various diseases. Their high binding sensitivity and specificity added by their small size have favored the identification by in vitro protocols. Molecular targeting has initiated exciting technologies based on conjugation of biomolecules to nanoparticles. This review article is an extensive study of various research oriented nanobiotechnological protocols for rapid identification and cure for prion diseases both at in vivo and in vitro options.