Bio-Reduced Graphene Oxide as a Nanoscale Antimicrobial Coating for Medical Devices

Antimicrobial coating on biomedical devices to prevent bacterial colonization is of great interest in healthcare industry nowadays. In this context, graphene nanomaterial has created an excellent opportunity in the biomedical research. The whole cell biomass of Rhizopus oryzae has been explored as a reducing agent for eco-friendly synthesis of reduced graphene oxide (rGO) and minimizing the extensive use of toxic chemicals. The as-synthesized rGO was then characterized by UV-vis spectroscopy, thermo gravimetric analysis, and high-resolution transmission electron microscopy (HRTEM) studies. The hydrodynamic size and surface charge were analyzed by dynamic light scattering and zeta potential studies, and the values were found to be 4350 +/- 25 nm and -21.2 +/- 5.22 mV, respectively. The HRTEM analysis depicted the ultrathin sheet-like morphology of rGO. The graphene oxide (GO) and as-prepared rGO were then coated onto the surface of aluminum plate for testing antibacterial properties. The attenuated total reflectance and Raman spectroscopic analyses were recorded to understand the coating of GO and rGO on the surface of aluminum plate, while surface morphology of the coated plates were analyzed by scanning electron and atomic force microscopy. The antibacterial activity was tested against Gram-negative bacteria Escherichia coli for both GO- and rGO-coated plates, which demonstrated excellent antibacterial activity of rGO-coated surface compared with that of the GO-coated plate. Additionally, the rGO-coated plate showed cytocompatibility when tested on 3T6 fibroblast cell line. The obtained result will therefore help to develop graphene-based nontoxic antibacterial coating for biomedical applications.