Staphylococcus epidermidis adhesion to films deposited from hydroxyethylmethacrylate plasma.

The adhesion of S. epidermidis ATCC 35984 strain on polystyrene (PS) disks coated by films deposited from hydroxyethylmethacrylate (HEMA) plasma was evaluated and compared to adhesion on untreated PS and oxygen-plasma-treated PS. Films were deposited keeping constant the monomer flow rate while the discharge power ranged from 40-100 W in order to obtain coating with different surface properties. Surface chemistry, energetics, and morphology were evaluated by Electron Spectroscopy for Chemical Analysis (ESCA), contact angle measurement, and Atomic Force Microscopy (AFM), respectively. Bacteria adhered more to the plasma-deposited or plasma-treated surfaces than to untreated PS, but no significant difference was recorded among the samples obtained using different deposition conditions. According to the surface energetic analysis, plasma-deposited and plasma-treated surfaces bear a strong Lewis-base character, so it is possible to hypothesize a marked contribution of electron donor-electron acceptor interactions to the mechanism(s) controlling adhesion between synthetic and bacterial surfaces.