The effect of surface properties of EVAL membranes on the inflammatory response

The purpose of this study was to examine the relationship between tissue response and the membrane surface structure. A series of ethylene vinyl alcohol (EVAL) membranes provide an ideal system for a study of the relative contributions to biocompatibility derived from the surface morphology. This is different from other reports using different kinds of polymers, which may thus result in considerable variation since polymer implants are both chemically and physically heterogeneous. This study demonstrated that the tissue response to three different membrane structures were quite different. Flat and dense EVAL surfaces induced a mild foreign body reaction indicating that EVAL copolymer does not provide a stimulus for a continued inflammatory response. The inflammatory response was strong using a porous surface and a surface with a particulate morphology. In addition, particulate surfaces provoked a more intense inflammatory response than porous surfaces, indicating that a material in particulate form, suitable for phagocytosis, may provoke a different degree of inflammatory response than the same material in a nonphagocytosable form. Therefore, although a material may be considered to be biocompatible, however, its surface properties may alter the observed tissue reaction and inflammatory response. Consequently, the surface properties should be suitably selected according to the purpose for which the material is to be used.