Bio-Assisted and Organic-Mediated Synthesis of Metal Oxide Nanoparticles: Structure–Property Relationships and Biomedical and Environmental Applications

Abstract

Currently, metal oxides and nanometallic materials have gained significant attention and functional versatility due to their unique properties, including their tunable electronic structure and structural variety, which offer promising applications in various fields. The unique characteristics exhibited by these oxides can be exploited in photocatalysis, sensing, ecological remediation, energy storage, and biomedical technologies, all these applications from the effects of quantum size, promoted surface-to-volume ratios, as well as surface defect. Biological and green organic strategies have emerged as sustainable alternatives, given that traditional methods require toxic materials, consume high energy, and have restricted control over surface functions. Among these biological strategies, plant extracts or biopolymers are used as stabilizers and reducing agents, while organometallic and chelating complexes are employed as organic methods. This review provides a comprehensive analysis of the formation of nano metal oxides, focusing on morphology control and surface defect engineering. The analysis also includes a comparison between biological and organic approaches, examining aspects such as environmental impact, reproducibility, and scalability. Furthermore, it meticulously examines the relationships between structural parameters and functional properties, including biological and organic behavior. Current challenges, sustainable sights, and the trends for future are also considered. Linking mechanisms with structural relationships and application-based insights, this review presents a structure for the sustainable strategy of metal oxide nanoparticles as an environmentally friendly technology.