Resumen de Synthesis and Characterization of Nanoselenium: A Step-by-Step Guide for Undergraduate Students
Gagan Dhawan, Indu Singh, Uma Dhawan, Pradeep Kumar
Nanoparticle synthesis is an important area of nanotechnology and has been performed by undergraduate students frpm various universities across the globe. Due to the availability of massive data on the synthesis of a wide variety of metallic nanoparticles, including silver, gold, selenium, zinc, copper, iron, palladium, platinum, titanium, etc., and their oxides, it has become tedious to select an ideal and workable protocol for their synthesis. Herein, we have focused on the standardized chemical and biological methodologies to prepare selenium nanoparticles (SeNPs or nanoselenium). Chemical methods exploit chemicals such as sodium selenite (Na2SeO3) and reductants (l-ascorbic acid, glutathione, etc.), along with stabilizing agents (Polysorbate 20, protic acid, lysozyme). Although these methods have been used for commercial purposes, they suffer from several drawbacks such as the use of excessive additives for controlled morphology, multistep synthesis, high running cost, and environmental toxicity. Biogenic synthesis using plant materials and microorganisms (algae, fungi, yeast, bacteria, and viruses), on the other hand, is a sustainable, environment-friendly, and cost-effective approach. The natural reducing agents facilitate the conversion of selenium salts into nanosized selenium particles in a single step and act as capping and stabilizing agents, which impart synergism in biological activities. Physical methods such as hydrothermal, irradiation, pulsed laser ablation, etc., have also been used for their production; however, high cost, stringent conditions, and high energy consumption have hampered their applications. Herein, we present a step-by-step methodology using chemical and biological reducing agents to synthesize selenium nanoparticles which will assist the undergraduate learners in selecting a well-tested method based on the conditions of an experiment and desired applications.
