Extracellular biosynthesis of magnetic iron oxide nanoparticles by Bacillus cereus strain HMH1: Characterization and in vitro cytotoxicity analysis on MCF-7 and 3T3 cell lines.

Discovery of new properties and special functionalities at the nanoscale materials caused nanotechnology to become one of the leading parts in all sciences namely biology and medicine. Magnetic iron oxide nanoparticles (MIONPs) are among interesting nanomaterials in biomedical arena, which have attracted the attention of many researchers owing to their extensive capabilities. Due to the simple, cost-effective and environmentally-friendly production processes, biosynthesis is of paramount importance between different methods of nanoparticles production. In the current study, we succeeded to synthesize MIONPs using a newly extracted bacteria supernatant. Produced nanoparticles were characterized using FE-SEM, DLS, VSM, UV-vis, FT-IR and EDS spectroscopy. Analysis showed that the average particle size of very stable spherical MIONPs is about 29.3 nm. The bacteria protein profile obtained by SDS-PAGE analysis indicated induction of different proteins. In vitro cytotoxicity of nanoparticles on the viability of MCF7 and 3T3 cell lines was assessed by MTT assay. The results show that toxicity of the produced nanoparticles (IC50, MCF-7  > 5 mg/ml and IC50, 3T3  > 7.5 mg/ml) follows a concentration dependent manner.