Antibacterial activity of fluorinated diamond-like carbon films produced by PECVD

Diamond-like carbon (DLC) films have been the focus of extensive research in recent years due to its potential application as surface coatings on biomedical devices. It has been already reported that fluorine (F) could increase DLC antibacterial activity. In this paper we investigated the antibacterial activity of fluorinated-DLC (F-DLC) films with various F contents and its correlation with bacterial adhesion mechanism according to thermodynamic theory. F-DLC was grown on a 316L stainless steel substrate using plasma enhanced chemical vapor deposition (PECVD) by varying the ratio of carbon tetrafluoride and methane. The antibacterial tests were performed against E. coli and the influence of F content on composition, surface energy, stress and surface roughness was also investigated. As F content increased, F-DLC films presented lower stress and surface free energy. In addition, the roughness values increased and Raman G-band peak position shifted to higher wave numbers. The results show that bacterial adhesion to F-DLC films decreases with increasing F content and work of adhesion, which is consistent with the thermodynamic theory. PECVD is a simple technique to produce F-DLC films to be used in biomedical applications.