No abstract

Nanozymes are artificial enzyme systems which are easy to produce, highly stable and cost‐effective in comparison to natural enzymes. Herein, we evaluated the peroxidase‐like activity of gold nanorattles (Au NRTs) having a solid gold octahedron core and thin, porous cubic gold shell. We also prepared solid gold nanocubes and nanospheres of similar sizes and surface charge as that of Au NRTs and compared their activity with standard horse radish peroxidase (HRP). All the prepared nanostructures followed Michaelis‐Menten kinetics as observed from their substrate concentration vs. initial reaction velocity plot using 3,3’,5,5’‐tetramethylbenzidine (TMB) as a substrate. The kinetic parameters and the catalytic efficiency for the peroxidase‐like activity of the nanostructures and HRP were calculated, and it was observed that Au NRTs possess the best nanozymatic activity with lowest KM and highest catalytic efficiency (kcat/KM). The better activity of Au NRTs compared with other nanostructures and HRP could be attributed to the hollow porous structure with a solid core where different surfaces are available for reaction. Au NRTs, being the best amongst the tested nanozymes were further used for the sensing of hydrogen peroxide (H2O2) and were found to sense H2O2 down to 0.5 μM. Further, two naturally occurring antioxidants, tannic acid and ascorbic acid showed inhibitory effect on the peroxidase‐like activity of Au NRTs in a concentration dependent manner which can be further used for screening of antioxidants or for determining the antioxidant potential.

No abstract

The continuous and excessive use of agrochemicals for the crop improvement and protection has raised a widespread concern, as they exert adverse effects on human health and local environment. Surface...

The outbreak of SARS-CoV-2 is unlikely to be contained anytime soon with conventional medical technology. This beckons an urgent demand for novel and innovative interventions in clinical protocols, diagnostics, and therapeutics; to manage the current "disease X" and to be poised to counter its successor of like nature if one were to ever arise. To meet such a demand requires more attention to research on the viral-host interactions and on developing expeditious solutions, the kinds of which seem to spring from promising domains such as nanotechnology. Inducing activity at scales comparable to the viruses themselves, nanotechnology-based preventive measures, diagnostic tools and ther-apeutics for COVID-19 have been rapidly growing during the pandemic. This review covers the recent and promising nanomedicine-based solutions relating to COVID-19 and how some of these are possibly applicable to a wider range of viruses and pathogens. We also discuss the type, composition, and utility of nanostructures which play various roles specifically under prevention, diagnosis, and therapy. Further, we have highlighted the adoption and commercialization of some the solutions by large and small corporations alike, as well as providing herewith an exhaustive list on nanovaccines.