Streptomyces-Mediated Green Synthesis of Nanoparticles: Mechanisms, Applications, and Future Perspectives

Abstract

Streptomyces species are prolific producers of bioactive secondary metabolites, enzymes, and reducing agents, making them attractive biotechnological platforms for the eco-friendly synthesis of metallic and metal oxide nanoparticles. Their ability to generate nanoparticles under mild and sustainable conditions has stimulated growing interest in biomedical, agricultural, and environmental applications. This review evaluates the current knowledge on Streptomyces-mediated nanoparticle biosynthesis, focusing on the underlying synthesis mechanisms, biological applications, cytotoxicity profiles, limitations, and future research directions. Published literature on the biosynthesis of silver, gold, zinc oxide, copper oxide, iron oxide, and selenium nanoparticles by Streptomyces species was critically examined. Particular attention was given to nanoparticle formation mechanisms, physicochemical characteristics, therapeutic potential, and safety considerations. The reviewed studies demonstrate that Streptomyces-derived nanoparticles exhibit diverse bioactivities, including antimicrobial, antioxidant, wound-healing, and anticancer effects. Their biological performance is strongly influenced by physicochemical parameters such as particle size, morphology, surface charge, concentration, and exposure duration. Although these nanomaterials can selectively induce cancer cell death through reactive oxygen species generation, mitochondrial dysfunction, and apoptosis, evidence also indicates potential adverse effects in normal cells, including oxidative stress, DNA damage, inflammation, and organ toxicity. Important knowledge gaps remain regarding long-term biodistribution, bioaccumulation, immunogenicity, and environmental fate. Despite their considerable promise, the translation of Streptomyces-derived nanoparticles into clinical and commercial applications is constrained by limited standardization, scalability challenges, insufficient long-term toxicity data, and evolving regulatory requirements.