Progress in the microbial synthesis and biomedical applications of silver and gold nanoparticles

Nanoscience has revolutionized materials synthesis, with noble metal nanoparticles like silver and gold gaining prominence for their unique physicochemical and biological properties. Microbial synthesis offers a sustainable, biocompatible alternative to conventional methods, leveraging bacteria, fungi, and algae as natural biofactories to produce stable silver and gold nanoparticles via enzymatic reduction and biomolecule-mediated capping. Here, we review mechanisms of microbial nanoparticle biosynthesis, characterization techniques, and diverse biomedical applications, including antimicrobial, anticancer, antioxidant, drug-delivery, imaging, and wound-healing functionalities. However, despite their promise, challenges related to toxicity, consistency, process scalability, batch-to-batch variation, and regulatory compliance remain significant concerns. Thus, a thorough assessment of nanoparticle physicochemical properties, biosafety, and therapeutic effectiveness is crucial to advance clinical applications. Overall, microbial nanotechnology offers a promising avenue for biomedical use, but further refinement and standardized assessments are needed to enable reliable, scalable applications. Key points Microbial synthesis of silver and gold nanoparticles is sustainable and biocompatible.Diverse microorganisms act as natural nanofactories capable of producing stable AgNPs and AuNPs.Silver and gold nanoparticles exhibit broad biomedical potential.