ADHESION OF STAPHYLOCOCCUS-EPIDERMIDIS TO BIOMEDICAL POLYMERS - CONTRIBUTIONS OF SURFACE THERMODYNAMICS AND HEMODYNAMIC SHEAR CONDITIONS

Adhesion studies of Staphylococcus epidermidis RP62A were conducted us ing a rotating disk system to determine the roles of surface physicoch emistry and topographies under physiologic shear conditions. Six mater ials were investigated: biomedical reference polyethylene and polydime thylsiloxane; argon plasma-treated reference polyethylene (Ar-PE); Sil astic(R); expanded polytetrafluoroethylene; and woven Dacron. All of t he polymers except Dacron demonstrated reduced bacterial adhesion with increasing shear stress. Argon plasma treatment of polyethylene reduc ed the level of staphylococcal adhesion. Adsorption of human plasma pr oteins effected significantly lower numbers of adherent bacteria. The lowest adhesion was observed for Ar-PE in 1% human plasma protein solu tion, whereas Dacron had the highest number of adherent bacteria. The high adhesion on Dacron was attributed to increased bacterial flux cau sed by topography-induced turbulent flow and physical entrapment of th e bacteria in the fiber interstices. The results indicate that the dri ving force for S. epidermidis adhesion is strongly influenced by subst rate physicochemistry, but this may be dominated by physical forces su ch as shear and turbulence. (C) 1995 John Wiley & Sons, Inc.