Biogenic Synthesis and Characterization of Silver Nanoparticles With Cyanobacterium Oscillatoria salina Using Against MDR Pathogenic Bacteria and Their Antiproliferative and Toxicity Study.

The biosynthesis of silver nanoparticles (AgNPs) using cyanobacteria has gained significant attention due to its cost-effective and eco-friendly advantages in green synthesis. Additionally, biogenic AgNPs show great potential for biological applications, particularly in combating infections caused by drug-resistant bacteria and fungi. This study synthesized using the cyanobacterium Oscillatoria salina (Os-AgNPs). The Os-AgNPs were characterized by a UV-vis spectral absorption peak at 447 nm, and their functional groups were identified through X-ray diffraction analysis, revealing a crystal structure with a 2θ value of 38°. Transmission electron microscopy (TEM) analysis showed an average nanoparticle size of 9.81 nm. The Os-AgNPs demonstrated remarkable antioxidant, antibacterial, and antifungal properties. Their antibacterial activity was tested against multidrug-resistant (MDR) Gram-positive bacteria, including Staphylococcus aureus, Streptococcus pyogenes, and Enterococcus faecalis, as well as Gram-negative bacteria such as Escherichia coli, Klebsiella pneumoniae, and Pseudomonas aeruginosa, all isolated from clinical samples. The inhibition zones for bacterial strains ranged from 15 to 20 mm, as measured by the agar-well diffusion method. Similarly, the Os-AgNPs exhibited antifungal activity, with 20-30 mm inhibition zones against pathogenic fungi Trichophyton rubrum and Candida tropicalis. Additionally, the antiproliferative effects of the Os-AgNPs were evaluated on human cancer cell lines, including HeLa (cervical adenocarcinoma) and MD-AMB-231 (breast adenocarcinoma). In vivo toxicity studies were conducted using Swiss mouse models to assess the cytotoxic effects. Overall, the results suggest that Os-AgNPs, biosynthesized using O. salina, hold promise as potential antimicrobial and anticancer agents for pharmaceutical applications.