Effects of silicon dioxide nanoparticles and nanodiamonds on intestinal commensal bacteria

Nanomaterials and nanotechnology have been widely applied in biological and biomedical field. Recent studies reveal that many nanomaterials possess antibacterial activities. While most of these studies focus on the ability of nanomaterials to inhibit the growth of pathogenic bacteria in vitro , few of them test the effects of nanomaterials on intestinal commensal bacteria. Here, we report that SiO 2 nanoparticles, but not nanodiamonds, can inhibit the growth of Drosophila intestinal commensal bacteria in vitro . Surprisingly, dietary SiO 2 nanoparticles of same dosage fail to display similar effects in Drosophila larvae. These results imply that the antibacterial effect of nanomaterials differs in vitro and in vivo . Comparing to in vitro environment, intestine can provide better environment for the growth of intestinal commensal bacteria and prevent the effects from exogenous nanomaterials.