Graphene oxide (GO) decorated on multi-structured porous titania fabricated by plasma electrolytic oxidation (PEO) for enhanced antibacterial performance

Plasma electrolytic oxidation (PEO) is proven as a scalable method for surface treatment of titanium (Ti) providing a thick oxide layer with porous micro-nano morphology. Despite the lack of antibacterial performance, this modification has potential to improve the osseointegration properties of Ti-based implant. To address this limitation, we demonstrated a new concept, showing that partial incorporation of graphene oxide (GO) to porous-PEO Ti-surface can significantly improve its antibacterial performance. Our idea for partial coating compared with a full surface coverage of GO was motivated to create a mixed surface with porous PEO and GO to improve antibacterial ability, while maintaining the osseointegration properties. To achieve these goals, we combined PEO and electrophoretic deposition process (EPD) to deposit GO sheets over the titanium PEO-treated substrate. The SEM, EDS, optical profilometry, XRD and Raman spectroscopy confirmed the growth of unique multi-structured porous PEO structures decorated with GO patches. The bio-mineralization test provided the evidence of hydroxyapatite formation over the PEO-GO surface, indicating its good bioactivity. Finally, PEO-GO samples demonstrated a superior antibacterial rate of ~80% against E.coli and ~100% against S. aureus. These results indicate that PEO-GO modified titanium substrates are very promising for the development of advanced biomedical implants.