Green synthesis of reduced graphene oxide by a GRAS strain Bacillus subtilis 168 with high biocompatibility to zebrafish embryos

Abstract

Low toxic and highly biocompatible graphene-based nanomaterials are in high demand within the biomedical fields. In this study, a highly biocompatible bacterially reduced graphene oxide (BRGO) was prepared by a “Generally Recognized As Safe” (GRAS) strain Bacillus subtilis 168 mediated with Vitamin K₃ (VK₃). The hypothesis of VK₃ mediating electron transfer between succinate:quinine oxidoreductase, from B. subtilis 168, and graphene oxide (GO) was proposed. BRGO was characterized by Raman spectroscopy, XPS and XRD and showed excellent properties. Furthermore, BRGO illustrates greater biocompatibility, with less toxicity, than GO and chemically reduced graphene oxide (CRGO) by zebrafish toxicity assessment, which demonstrates its great potential in various biomedical applications.