Fundamentals, Synthesis, and Antioxidant Applications of Zinc Oxide Nanoparticles: A Critical Review

Abstract

This comprehensive review examines zinc oxide nanoparticles (ZnO NPs), spotlighting their structural, optical, and catalytic fundamentals, diverse synthesis strategies, and emerging role as potent antioxidant agents. Their intrinsic traits, coupled with their biocompatibility and thermal stability, position them as versatile candidates for advanced applications. The synthesis of ZnO NPs is explored through scalable chemical, physical, and biological routes, including hydrothermal growth, chemical vapor deposition, sol-gel processing, microwave-assisted techniques, plant-mediated green synthesis, and precipitation methods. Each approach is critically analyzed for its impact on nanoparticle morphology, size distribution, and functional efficacy. A dedicated focus is placed on the antioxidant potential of ZnO NPs, where their ability to scavenge reactive oxygen species (ROS) and mitigate oxidative stress is dissected. This property underpins their therapeutic promise in combating inflammation, aging, and degenerative diseases, as well as their environmental utility in neutralizing pollutants and stabilizing industrial products. By bridging material science with biomedical and environmental research, this review underscores the transformative potential of ZnO NPs while advocating for rigorous safety assessments to address toxicity concerns. The integration of fundamental insights, synthesis optimization, and application-driven innovation outlined here aims to guide future advancements in nanotechnology, healthcare, and sustainable engineering.