EPA covalently bound to smooth titanium surfaces decreases viability and biofilm formation of Staphylococcus epidermidis in vitro

Colonization of implant surfaces with bacteria should ideally be prevented right from implantation, as bacteria attaching to the surface will form a biofilm, being then well protected against antibiotic treatment. Therefore, implant coatings should combine antibacterial properties with biocompatibility towards their host tissue. We tested a UV-induced covalent coating procedure with eicosapentaenoic acid (EPA) for smooth titanium (Ti) surfaces for its ability to prevent attachment and proliferation of Staphylococcus epidermidis and to allow mineralization of MC3T3-E1 osteoblasts. Bacterial initial attachment was highest for EPA-coated surfaces, but was reduced by vigorous washing, possibly due to low adhesive strength on those surfaces. We found an increase in the ratio of dead bacteria and in overall biofilm after 16?h on Ti surfaces with covalently bound EPA compared to Ti. The UV-induced EPA coating did not impair the ability of MC3T3-E1 preosteoblasts to mineralize, while a reduction in mineralization could be found for UV-irradiated Ti surfaces and UV-irradiated surfaces washed with ethanol compared to Ti. Although in vivo studies are needed to evaluate the clinical significance, our results indicate that covalent coating of Ti surfaces with EPA by UV irradiation decreases the survival of S. epidermidis and maintains the mineralization ability of osteoblasts. (C) 2012 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 30:13841390, 2012