Biofabrication of silver nanoparticles using Lactobacillus casei subsp. Casei and its efficacy against human pathogens bacteria and cancer cell lines

Bio-fabrication of metallic nanoparticles is interesting research field because of its different potential applications in nanomedicine.
In the present work, human strain probiotic Lactobacillus casei subsp. Casei was used as potential bioreductant for the synthesis of
silver nanoparticles (AgNPs), its antimicrobial and anticancer properties were evaluated. The synthesized nanoparticles were
characterized using UV–visible spectroscopy, Fourier-transform infrared spectroscopy (FT- IR) and Transmission electron microscopy
(TEM). Biosynthesized silver nanoparticles were confirmed by color changes and were found to be spherical in shape and well
dispersed, with no agglomeration. Antimicrobial and anticancer activities of silver nanoparticles were evaluated against selected
pathogens (Staphylococcus aureus, Pseudomonas aeruginosa) and human gastric carcinoma cells (AGS) and Human Colon
Carcinoma cells (HT-29). Results showed that biosynthesized AgNPs had excellent antibacterial activities against Staphylococcus
aureus and Pseudomonas aeruginosa which were observed by well diffusion, minimum inhibitory concentration (MIC) methods.
These nanoparticles were able to inhibit proliferation of human cancer cell lines. Ag NPs were shown to promote apoptosis as seen
in the acridine orange/Propidiom Iodide staining and increase nitric oxide (NO) secretion determined by NO production assay. Our
results are promising for potential use of the biosynthesized Ag NPs as an antibacterial and anticancer agent. Lactobacillus casei
subsp. Casei can act as a novel source for AgNPs biosynthesis. This method can be employed for development of new nano-drug
formulations in cancer therapy.