Silver Nanoparticles (AgNPs): Comprehensive Insights into Bio/Synthesis, Key Influencing Factors, Multifaceted Applications, and Toxicity—A 2024 Update

Abstract

Silver nanoparticles (AgNPs) are widely recognized for their unique optical, electronic, and antibacterial properties, enabling their use in biosensing, photonics, electronics, drug delivery, and antimicrobial treatments. Green chemistry-based biological synthesis methods offer an eco-friendly alternative to traditional chemical techniques. Among metallic nanoparticles (NPs) and metal oxides, those derived from plant extracts exhibit notable medicinal properties. Due to their exceptional stability and low chemical reactivity, AgNPs are particularly well-suited for various biological applications. AgNPs can be synthesized through chemical, physical, or biological methods, each with distinct benefits and challenges. Chemical and physical approaches often involve complex purification, reactive reagents, and high energy demands, while biological methods, though slower, provide sustainable solutions. The chosen synthesis method strongly influences the stability, size, and purity of the resulting NPs. This review emphasizes the importance of selecting appropriate synthesis methods to optimize the characteristics and functionality of silver NPs. It consolidates research spanning the past two decades, including the most recent findings from 2024. A comprehensive electronic search of databases such as PubMed, Scopus, ScienceDirect, Cochrane, and Google Scholar was conducted to provide an up-to-date overview of advances in the synthesis and applications of silver nanoparticles.