Biogenic Synthesis of ZnO Nanoparticles and Their Application as Bioactive Agents: A Critical Overview

Abstract

Zinc oxide is a safe material for humans, with high biocompatibility and negligible cytotoxicity. Interestingly, it shows exceptional antimicrobial activity against bacteria, viruses, fungi, etc., especially when reduced to the nanometer size. As it is easily understandable, thanks to its properties, it is at the forefront of safe antimicrobials in this pandemic era. Besides, in the view of the 2022 European Green Deal announced by the European Commission, even science and nanotechnology are moving towards “greener” approaches to the synthesis of nanoparticles. Among them, biogenic ZnO nanoparticles have been extensively studied for their biological applications and environmental remediation. Plants, algae, fungi, yeast, etc., (which are composed of naturally occurring biomolecules) play, in biogenic processes, an active role in the formation of nanoparticles with distinct shapes and sizes. The present review targets the biogenic synthesis of ZnO nanoparticles, with a specific focus on their bioactive properties and antimicrobial application.