Sustainable nanobiotechnology: Plant-mediated metallic nanoparticles for antimicrobial innovations

Antimicrobial resistance (AMR) is a growing global health threat that increases the disease burden, mortality, and healthcare costs. As new antibiotics become scarce and multidrug-resistant bacteria increase, alternative strategies are needed. Metal and metal-oxide NPs have emerged as promising antibacterial agents owing to their unique properties, broad-spectrum activity, and reduced potential for resistance development. Green synthesis leverages biological resources, including plant extracts, microorganisms, and bioactive metabolites, as a sustainable, cost-effective, and eco-friendly alternative to conventional chemical and physical synthesis methods. Plant-based synthesis is particularly attractive because of its simplicity, scalability, and ability to produce stable, biocompatible NPs under mild conditions. However, several challenges remain, including the unpredictable behavior of biological precursors, limited control over NP size and shape, stability issues, and difficulties in large-scale production, all of which hinder broader industrial and clinical adoption. This review highlights the latest advances in green NP synthesis, critically examines their antibacterial mechanisms and biomedical applications, and identifies current limitations and future research directions. To achieve the full potential of green-synthesized nanoparticles, standardized protocols and optimized reaction parameters are required.