Modern Approaches to Silver Nanoparticle Synthesis and Their Functional Roles

Silver nanoparticles (AgNPs) have quickly become one of the most widely studied nanomaterials because of their unique physicochemical properties and the vast application space they occupy. In this review paper, we present a comprehensive literature assessment of current synthesis methods for AgNPs, particularly how differing material precursors influence nanoparticle properties and functional performance. Traditional synthesis approaches (chemical and physical) are specific and provide excellent control over size and shape, but are subject to environmental and human health concerns while (green) synthesis approaches using extracts from plants, as well as microorganisms and enzymes, are more sustainable and biocompatible but have issues around reproducibility. We highlight the role of material precursors (especially plant-based systems) on producing stable AgNPs with bioactive surface coatings, and assess functional applications - in four broad areas being antibacterial, antioxidant, biomedical, and environmental. We discuss the mechanism of activity for AgNPs, including membrane disruption, generation of reactive oxygen species (ROS), and catalytic degradation of environmental pollutants. While the functional advantages of AgNPs are clear, we note concerns around AgNP toxicity (in particular related to bioaccumulation and persistence in ecosystems). To manage these risks, the review emphasizes the necessity of safe-by-design strategies, surface functionalization strategies, and strong regulatory frameworks. Ultimately, AgNPs will advance if safety and sustainability are balanced with innovation. The review helps advance these efforts by bringing together contemporary studies and considering future pathways of research and applications.