Selective toxicity of mycosynthesized zinc nanoparticles toward colon cancer and its most associative pathogen (Streptococcus gallolyticus)

Colon cancer is one of the most common causes of cancer-related deaths worldwide. Streptococcus bovis (currently Streptococcus gallolyticus) is considered a silent sign of colon malignancy diseases. As best of our knowledge this study is the first report dealt with collective elimination of colon cancer and its most associative pathogen (S. gallolyticus). Few attempts have been made to investigate the feasibility of using fungi to synthesize ZnNPs. Biosynthesis of zinc nanoparticles using Epicoccum nigrum (ATCC 48203) was achieved in the current study. Mycosynthesized ZnNPs were characterized using UV-visible spectrophotometer, Energy Dispersive X-ray (EDX) and transmission electron microscope (TEM). Mycosynthesized ZnNPs exhibited promising antibacterial activity in vitro against S. gallolyticus which have been visualized using Scanning and transmission Electron Microscopes (SEM &TEM). Cytotoxicity profiles of malignant and normal colon cells treated with mycosynthesized ZnNPs in vitro suggested that ZnNPs exhibited a preferential ability to kill cancerous colon cells than normal colon cells as visualized by Inverted microscope, SEM and TEM. Selective cytotoxicity of ZnNPs might be due to increased Reactive Oxygen Species (ROS) generation % in HCT-116 and S. gallolyticus treated with ZnNPs compared with normal colon cells treated with ZnNPs. This finding makes ZnNPs a promising anticancer and antibacterial agent.