Biogenic Synthesis of Selenium Nanoparticles using Diospyros montana Bark Extract: Characterization, Antioxidant, Antibacterial, and Antiproliferative Activity

Introduction

Nanotechnology has evolved into a promising technology in the twenty-first century, allowing the fabrication of nanoscale structures with superior capabilities¹. These size-dependent capabilities give nanostructures an advantage over bulky materials in catalysis, electronics, biomedicals, therapeutics, and biosensing ². Nanoparticles have been the focal point of attention in therapeutics and medicine, owing to rapid advances in nanotechnology³; Nanomedicine is a term that describes the usage of nanotechnology in disease detection, diagnosis, and treatment. This new field has shown the revolutionary potential of current diagnostics and treatment practices^{4, 5}. Green nanotechnology aims for a broad range of scientific goods and processes that are highly safe, energy-efficient, waste-free, and significantly reduce greenhouse gas emissions⁶. Green source-mediated synthesis allows for finely controlled nanoparticle size and shape, as plants serve as stabilizing and reducing agents⁷. Additionally, the therapeutic effect of biogenic nanoparticles is more significant than that of chemically produced nanoparticles^{8, 9}.

Selenium nanomaterials (Nano-Se) are new selenium sources with superior in-vivo bioavailability while minimizing the risk of selenium toxicity¹⁰. Selenium nanoparticles (SeNPs) have shown much more excellent biocompatibility and degradability in-vivo than metals of great worth, such as silver, gold, and platinum. Se in various nanoforms has also shown lesser toxicity and higher antioxidant and antitumor potential than organic and inorganic selenium types^{11, 12}. The activity of glutathione peroxidase (GSH-Px) and thioredoxin reductase is increased by nano-selenium with low toxicity and high antioxidant activity. As a result, nanoparticles may be helpful because the nanoparticle size affects biological activity^{13, 14}. Size-dependent binding of free radicals is possible with SeNPs varying in size from 5 to 200 nm. Chemical reduction is the most prevalent method for obtaining selenium nanoparticles in various ways¹⁵. In the fabrication of SeNPs, the green chemistry of synthetic methodologies using biological processes such as enzymes, microbes, and plant extracts plays a vital role¹⁶. Phytoextracts in the fabrication of SeNPs are the most environmentally friendly alternative to the current chemical and physical methods¹⁷. This technique is applied to reduce toxicity and generate green chemistry. The principal phytochemicals utilized to fabricate SeNPs are flavonoids, tannins, aldehydes, ketones, terpenoids, carboxylic acids, alkaloids, and quinones....