Aderaw Anteneh Belew, Shushay Hagos Gebre, Melesse Ababy Assege, Desta Shumuye Meshesha, Misganaw T. Ayana
The rapid advancement of nanotechnology has opened new avenues in medicine, electronics, environmental remediation, and energy. Among various nanomaterials, gold nanoparticles (AuNPs) have attracted significant attention due to their distinctive physicochemical characteristics, low toxicity, and broad application potential. This review aims to summarize the biosynthesis of AuNPs via green routes, including plants, bacteria, fungi, and algae, and to evaluate their biomedical, catalytic, and environmental applications. Key observations include their strong antibacterial, antifungal, antiviral, and biosensing activities, as well as their effectiveness in photocatalytic degradation of organic dyes. We also identify challenges in large-scale production, stability, and reproducibility, and highlight future directions for the development of sustainable, efficient, and multifunctional AuNPs. This review provides a comprehensive framework for researchers to advance green synthesis strategies and explore innovative applications of AuNPs.