Zinc oxide nanoparticles (ZnONP) have attracted significant attention due to their distinctive physicochemical properties, including a wide band gap, high chemical stability, and strong interaction with biological molecules, which enable diverse applications in biomedical, electronic, and environmental fields. In recent years, rapid expansion of nanotechnology has intensified interest in sustainable and biocompatible synthesis approaches for ZnONP. Conventional chemical and physical synthesis methods often involve toxic reagents, high energy consumption, and environmentally hazardous by-products, which limit their suitability for large-scale production and biomedical applications. Consequently, green synthesis strategies using plant extracts, microorganisms, and other biological resources have emerged as promising alternatives for producing ZnONP with improved biocompatibility and reduced environmental impact. This review critically examines the current progress in the biosynthesis of ZnONP, highlighting the underlying synthesis mechanisms, key parameters influencing nanoparticle formation, and commonly used characterization techniques. In addition, recent developments in the application of ZnONP in biomedical therapeutics, environmental remediation, and electronic devices are discussed to illustrate their growing technological relevance. Besides, outlines existing challenges, including scalability, reproducibility, and standardization of biosynthetic methods, and provides future perspectives for advancing sustainable production and expanding the practical applications of ZnONP.
Lakshmipriya et al. (Mon,) studied this question.