Evaluation of Antibacterial and Cytotoxic Properties of a Fluorinated Diamond-Like Carbon Coating for the Development of Antibacterial Medical Implants

Peri-implant infection is a serious complication in surgical procedures involving implants. We conducted an in vitro study to determine whether the use of a fluorinated diamond-like carbon (F-DLC) coating on a titanium alloy surface can prevent peri-implant infection. After applying the F-DLC, we evaluated its antibacterial and cytotoxic properties. The coating groups, containing controlled fluorine concentrations of 5.44%, 17.43%, 24.09%, and 30%, were examined for the presence ofStaphylococcus aureusandEscherichia coliaccording to ISO 22196 for the measurement of antibacterial activity on plastics and other nonporous surfaces. Biological toxicity was evaluated using Chinese hamster V79 cells according to ISO 10993-5 for the biological evaluation of medical devices. In the control group, populations ofS. aureusandE. colisubstantially increased from 2.4 x 10(4)to (1.45 +/- 1.11) x 10(6)colony-forming units (CFUs) and from 2.54 x 10(4)to (4.04 +/- 0.44) x 10(6)CFUs, respectively. However, no bacteria colonies were detected in any F-DLC group with a fluorine concentration of >= 17.43%. In the biological toxicity study, an F-DLC coating with a fluorine concentration of 30% showed a colony formation rate of 105.8 +/- 24.1%, which did not differ significantly from the colony formation rate of 107.5 +/- 31.1% in the nontoxic control group. An F-DLC coating on titanium alloy discs showed excellent in vitro antibacterial activity with no biological toxicity.