Bacteria against bacteria: Green silver nanoparticle fabrication, antioxidant, anti-biofilm and antibacterial activities

Abstract

The current study focuses on the assessment of antioxidant and antibacterial properties of Ag nanoparticles (NP) synthesised using a pathogen Shigella flexneri 29508 in a green synthesis techinque. The synthesis has been confirmed with evolution of surface plasmon resonance band in the absor[ption spectrum of Ag-NPs. The nanosize, homogeneity, and high stability of the particles are confirmed by dynamic light scattering technique. Spherical morphology with an average particle size of 50 nm has been observed by TEM analysis. EDAX clearly demonstrated the presence of elemental silver. Using conventional tests, the antioxidant capacity of the greenly produced Ag-NPs has been assessed. The results showed considerable antioxidant potential, demonstrating the potential of nanoparticles to combat free radicals and guarding against oxidative stress. Additionally, a small number of clinically significant bacterial strains have been used to test the antibacterial effectiveness of the produced Ag-NPs. To assess the detrimental impact of the nanoparticles on bacterial development, Resazurin-based micro-dilution viability test, disc diffusion, and spread plate assay techniques for MIC and MBC determination have been used. The results showed that the tested bacterial infections are resistant to a variety of powerful antibacterial agents in various degrees. Additionally, two biofilm-forming bacterial strains have been used to test the biosynthesized Ag-NPs' biofilm inhibitory and eradicating activities, and the findings demonstrated its powerful anti-biofilm potential. The success of the green synthesis of Ag-NPs utilizing bacteria is highlighted in this study, and their antioxidant, antibacterial, and antibiofilm properties are discussed.