Antimicrobial Properties of Graphite and Coal-Derived Graphene Oxides as an Advanced Coating for Titanium Implants

Prosthetic joint infection (PJI) poses a significant risk to implanted patients, requiring multiple surgeries with high rates of reinfection. The primary cause of such infections is otherwise innocuous bacterial species present on the skin that have survived sterilization protocols. Antibiotic drugs have significantly reduced efficacy due to the lack of vasculature in the newly implanted site, allowing microbes to form biofilms with even greater resistance. Graphene oxide (GO) is known to have good biocompatibility while providing drugless antimicrobial properties. The focus of this study is on the development and characterization of a robust coating for titanium alloy implants to promote bone regeneration while inhibiting microbial biofilm adhesion to the implant surface. The novelty of this study is the use of proprietary coal-derived graphene oxide (c-GO) in a biomedical application. c-GO has been demonstrated to have a greater number of functional oxygen groups to promote cell adhesion, while also maintaining thinner layers than possible with graphite exfoliation methods. As an alternative to powerful antimicrobial drugs, it was hypothesized that an advanced coating of graphene-oxide would provide a defensive, passively antimicrobial layer to a titanium implant. While GO is typically quite expensive, the newly developed process provides an economical and environmentally friendly method of producing GO from coal (c-GO). The result is a coating that is inexpensive and capable of halving the biofilm formation of MRSA on titanium-alloy surgical screws in addition to providing improved bone cell adhesion and hard tissue compatibility.