Green synthesis of silver nanoparticle using Oscillatoria sp. extract, its antibacterial, antibiofilm potential and cytotoxicity activity

Green route biosynthesis of silver nanoparticles (SNPs) using methanol extract of Oscillatoria sp. was investigated. The nanoparticles (OsSNPs) were characterized by UV-Vis spectrophotometry, FTIR, SEM, Thermogravimetry, EDX and DLS. The antibacterial, antibiofilm and in vitro cytotoxicity activity of the OsSNPs was determined. Surface Plasmon Resonance peak was at 500 nm. Functional groups such as hydroxyl; alcohol, phosphate, and amine among others were responsible for the capping and stabilization of proteins in the nanoparticles. The OsSNPs were spherical with size of 10 nm and are thermostable to an extent without totally losing its weight. EDX analysis revealed a strong signal of silver element. DLS shows the particle diameter average of 0.000 nm and 558.1 nm with a polydispersity index of 0.580. The OsSNPs had effective antibacterial activity against the test bacterial pathogens with zone of inhibition ranged from 1 - 21 mm. OsSNPs exhibited strong antibiofilm activity. However, the toxicity of the OsSNPs to Artemia salina (brine shrimp) was observed to be insignificant with the highest mortality at 4000 μg/mL and lethal dose (LC₅₀) of 2630.3 μg/mL. Greenly synthesized OsSNPs had effective antibacterial potency and low cytotoxicity which suggests its use in biomedical and pharmacological applications.