Antibacterial Coatings for Biomedical Applications

Diamond like carbon (DLC) and Ag-doped DLC (Ag-DLC) films were prepared by dual pulsed laser deposition using graphite and silver targets and two KrF excimer lasers. The silver concentration in the films was varied from 1.1 to 9.3 at. %. The surface topography was analysed by atomic force microscopy. The pure DLC was very smooth, but the roughness increased with rising silver content. Ethylene glycol, diiodomethane and deionized water were used to measure contact angles (CA). The measurements for water showed that the CA of Ag-DLC films (78–98°) was higher than that of the DLC film (77°). In order to understand the influence of incorporated Ag on the wettability, the surface energy and the protein adsorption as an indirect measure of the hemocompatibility were calculated. The surface energy of DLC and Ag-DLC films was same. The hemocompatibility was examined by the adsorption ratio of albumin/fibrinogen as an indirect method and improved with the increase of the Ag concentration. The antibacterial activity of the films were evaluated by bacterial eradication tests with Staphylococcus aureus and Pseudomonas aeruginosa at different incubation times. DLC and Ag-DLC films demonstrated good results against Staphylococcus aureus and Pseudomonas aeruginosa, meaning that DLC and Ag-DLC can be useful to produce coatings with antibacterial properties for biomedical devices such as sensors.