Biogenic Synthesis and Antibacterial Activity of Silver Nanoparticles Using Cyanobacteria From the Arid Region of Hail, Saudi Arabia

This research paper examines the biogenic production of silver nanoparticles (AgNPs) using cyanobacterial strains (Spirulina, Nostoc, and Anabaena) that have been isolated in arid areas, Hail, in Saudi Arabia, and determines their antimicrobial effects in relation to multi-drug-resistant pathogens. Synthesis was done by incubating cyanobacterial biomass with silver nitrate in controlled conditions, and the nanoparticle was analyzed through the use of UV-Vis spectrophotometry, transmission electron microscopy (TEM), and X-ray diffraction (XRD). The agar well diffusion technique was used to determine the antimicrobial activity against Escherichia coli, Staphylococcus aureus, and Pseudomonas aeruginosa. The statistical analysis (ANOVA) indicated that the cyanobacterial strain played an important role in the nanoparticle production as well as antimicrobial activity, and the F-value was 604.06 (p-value 1.21 x 10 -7). Based on the analysis of the antimicrobial activity, Nostoc-derived AgNPs had the best antimicrobial activity that was most effective in terms of the greatest zone of inhibition and lowest minimum inhibitory concentration (MIC) compared to Spirulina and Anabaena. The XRD pattern revealed that there were great variations among the crystallinity rates, with the best being the crystalline structure of Nostoc (p = 0.0258, F-value = 7.15). The MICs of AgNPs produced in Anabaena were also significantly smaller, which implies a greater antibacterial activity. Such findings present a positive indication that cyanobacterial strains, especially Nostoc, have potential in the biogenic synthesis of AgNPs with high antimicrobial qualities. The research concludes that AgNPs produced with Cyanobacterium can be used as a good and greener alternative antimicrobial agent, especially against resistant microbes, and recommends that further research be aimed at improving synthesis factors and investigating biomedical uses.