Green Synthesis of Metal Nanoparticles Using Microbial and Plant Extracts for Biomedical Applications

Abstract

Green synthesis of metal nanoparticles using microbial and plant extracts has emerged as an environmentally sustainable and biologically compatible strategy for developing advanced nanomaterials for biomedical applications. Conventional physicochemical synthesis methods often involve toxic reducing agents, high energy requirements, and hazardous by-products that limit clinical applicability and ecological safety. In contrast, green synthesis employs natural biomolecules from microorganisms such as bacteria, fungi, and algae, as well as phytochemicals present in plant extracts, to reduce metal ions into stable nanoparticles under mild and eco-friendly conditions. These biological entities provide dual functionality by acting as reducing and capping agents, thereby controlling nanoparticle nucleation, growth, morphology, and stability. Green-synthesised metal nanoparticles exhibit enhanced surface functionalization, improved dispersibility, and reduced cytotoxicity, which significantly enhance their biomedical performance. Recent studies demonstrate their broad-spectrum antimicrobial, anticancer, antioxidant, anti-inflammatory, and wound healing properties, along with promising roles in targeted drug delivery, biosensing, and diagnostic imaging. Moreover, the synergistic interaction between metal cores and bioactive surface molecules contributes to improved cellular uptake and therapeutic efficacy. Despite challenges related to reproducibility, standardization, and large-scale production, green synthesis remains a cost-effective and sustainable platform for producing multifunctional nanotherapeutics. This approach integrates principles of green chemistry, microbiology, and nanotechnology, offering a promising pathway toward safer and more effective biomedical innovations.