A new approach for simultaneously improved osseointegration and antibacterial activity by electrochemical deposition of graphene nanolayers over titania nanotubes

Abstract

Simultaneous enhancement of osseointegration and bacterial infection prohibition through surface modifications is a challenging but promising approach to achieve durable implantation. To that end, we present a multifunctional surface coating composed of graphene nanolayers and hierarchical well-aligned TiO2 nanotubes with a nanoporous top layer (cRTNT). FESEM studies reveal tunable increasing island morphologies of graphene nanolayers (G) on cRTNT by a cyclic voltammetry process. XPS analysis shows that the enhanced interface chemistry is due to TiO2-carbon bonding. The roughness of the sample containing a medium amount of graphene, cRTNT-75%GO, was calculated ∼289 nm, which was 543% higher than the Ti6Al4V surface. ALP activity increases by more than 25% for cRTNT/GO samples compared to pure cRTNT. Fluorescent microscopy indicates an approximately 92% decrease in bacterial colony formation and up to 85% improvement in the number of bacteria per field on cRTNT with increasing graphene amount compared to the Ti-6Al-4V surface. Although the increasing amount of graphene up to 95% shows better antibacterial performance, it does not provide a proper surface for adhesion and growth of the bone cells. According to all bio-assays, the nanocomposite coating with a medium amount of graphene (cRTNT-75%G) is proposed as the best sample in terms of biological properties, including improving cell behavior and preventing infection.