Synthesis and Characterization of Biogenic Selenium Nanoparticles Made from Pathogenic Bacteria with Selective Antimicrobial Properties

Antimicrobial Resistance has become an urgent crisis for humanity. An alternative, non-resistant-inducing and effective way to treat infection is needed. Metallic Nanoparticles (NPs) have long been studied for their antimicrobial properties, yet cost, efficiency, processing difficulties and ecological safety prevent their clinical use. To remedy these challenges, biogenic synthesis of nanoparticles, specifically Selenium nanoparticles (SeNPs) are explored and presented as an alternative antimicrobial agent. Selenium NPs was synthesized using E. coli, P. aeruginosa, S. aureus and MRSA with final diameter of 80-120 nm by culturing bacteria cells in standard conditions and inoculating them with Selenium salt at the end of exponential growth phase. The nanostructures were characterized using Transmission Electron Microscopy (TEM) and Energy Dispersive X-Ray (EDX) to determine the chemical compositions and Inductively coupled plasma mass spectrometry (ICP-MS) to validate the chemistry within the samples. Nanoparticles were tested against E. coli, P. aeruginosa, S. aureus and MRSA for their ability to inhibit the bacterial growth through optical density measurements and colony forming unit assays. Biocompatibility tests of the nanoparticles with human HDF were accomplished, along with resistance studies by several rounds of exposure onto pathogens. Results indicate that SeNPs were successfully generated by all tested strains. The biogenic SeNPs exhibited antimicrobial properties, with log reduction ranging from 3 – 4 with crossed application and 5 – 6 with specific application. Cytotoxicity assays confirmed its safety profile against HDF cells. More significantly, biogenic SeNPs treatment did not induce resistance, in contrast with commercial penicillin and commercialized AgNPs. These findings confirm the viability of biogenic SeNPs as an easy, safe, cheap and effective treatment and a potential solution against the Antimicrobial Resistance Crisis.