Influence of interaction energy between Si-doped diamond-like carbon films and bacteria on bacterial adhesion under flow conditions

Diamond-like carbon (DLC) films, especially modified DLC films with doped elements as biomaterials for medical devices have been attracting great interest. In this article, the bacterial adhesion behavior on DLC films, Si-doped DLC films, and stainless steel 316L was investigated with Pseudomonas aeruginosa ATCC 33347, which frequently causes medical device-associated infections. This was done under laminar flow conditions in a flow chamber at 37 degrees C. The contact angles of the coatings and the biofilm were measured. Polar liquids of distilled water and ethylene glycol, and apolar liquid of diiodomethane were used as a probe for surface free energy calculations. The electron donor component gamma(-) of surface energy of Si-doped DLC films increased with increasing the silicon content in the DLC films. The experimental results showed that the surface energy of the coatings and the interaction energy between the coatings and bacteria in water had significant influences on bacterial adhesion. The extended DLVO theory was used to explain the adhesion behavior.