Biogenic Nanoparticles and Green Nanocomposites as Sustainable Antimicrobial Strategies Against Bacteria, Fungi and Viruses

The field of nanotechnology, specifically the manipulation of materials at the nanoscale (1–100 nm), has gained significant attention owing to its diverse applications in biotechnology, nanomedicine and environmental sustainability. While nanoparticles synthesised using green methods such as plants, fungi and bacteria offer eco-friendly alternatives to conventional nanoparticles, green composite nanomaterials, which integrate biogenic nanoparticles with natural polymers or fibres, provide enhanced stability, controlled release and multifunctional antimicrobial properties. For instance, silver nanoparticle–chitosan composites have been successfully applied in wound dressings and food packaging, demonstrating real-world applications. These green composites exhibit antimicrobial activity through mechanisms including reactive oxygen species generation, membrane disruption, ion release and biofilm inhibition. This review discusses methods for synthesising both green nanoparticles and composites, their antimicrobial efficacy against bacteria, fungi and viruses, and practical applications in the medical, agricultural and environmental sectors. Challenges related to toxicity, scalability and environmental impact are also highlighted. Overall, green composite nanomaterials represent a sustainable and effective strategy for combating microbial resistance and promoting global health.