Deciphering therapeutic efficacy of mycosynthesized silver nanoparticles using entomopathogenic fungi Metarhizium anisopliae against MCF-7 breast cancer cells in vitro

Green synthesis of silver nanoparticles has gained much interest over few decades in the field of biomedical research due to their ease of synthesis, cost effectiveness, enhanced bioactivity and biocompatibility compared to the chemical synthesis. Recent studies on silver nanoparticles have shown their potential in various fields like antimicrobial, anticancer, larvicidal, catalytic, and wound healing properties. In the present study, entomopathogenic fungi Metarhizium anisopliae was used to synthesize silver nanoparticles. These silver nanoparticles were synthesized and characterized using UV-Vis spectroscopy, FESEM, FETEM and FTIR. Compared to the chemically synthesized silver nanoparticles, the mycosynthesized silver nanoparticles (MaAgNP) showed high yield. The size of mycosynthesized silver nanoparticles was found to be 5-20 nm and was spherical in shape. FTIR results confirmed the possible functional groups that are responsible for the reduction of silver ions. The mycosynthesized silver nanoparticles showed cytotoxicity on human breast cancer cell line (MCF-7) and the calculated IC 50 value for MaAgNP was found to be 16.50 μg ml -1 whereas the chemically synthesized silver nanoparticles showed cytotoxicity but with increasing concentration, no further significant reduction in cell viability was observed. The possible reason behind improved cytotoxicity of MaAgNP can be the presence of extracellular secondary metabolites present in the fungal filtrate used to synthesize the nanoparticles. The MaAgNP was also observed to induce cell death through reactive oxygen species (ROS) generation.