Research Article

Optical and Antibacterial Investigation of Biogenically Synthesized Silver Nanoparticles

Abstract

Sustainable antibacterial materials are desperately needed due to the growing prevalence of bacterial infections that are resistant to drugs. At the same time, environmental concerns associated with conventional nanoparticle synthesis methods have encouraged the development of eco-friendly alternatives. In this study, silver nanoparticles were synthesized using a green, plant-mediated reduction method in which phytochemicals present in the plant extract acted as both reducing and stabilizing agents. The formation of AgNPs was verified through optical characterization techniques. The synthesized nanoparticles exhibited typical optical features, including a distinct surface plasmon resonance band and a clear photoluminescence emission peak in the near-UV region (∼ 330–335 nm). These optical properties indicate efficient electronic transitions and the presence of stable surface states in the nanoparticles. Using the agar diffusion technique, the antibacterial activity of the biosynthesised AgNPs was assessed against Gram-positive Staphylococcus aureus and Gram-negative Escherichia coli. The findings demonstrated that AgNPs exhibited noticeably more antibacterial activity when compared to silver nitrate and plant extract alone, indicating that silver’s bioavailability and antimicrobial efficacy are improved by nanoparticle production. A comparatively larger inhibition zone was observed for the Gram-negative bacterial strain, indicating that variations in bacterial cell wall structure may influence nanoparticle susceptibility. Overall, the findings show that green-synthesised silver nanoparticles have potential for use in the pharmaceutical and biomedical industries and can function as potent antibacterial agents.