Plasma treatment of amorphous and semicrystalline polymers for improved biocompatibility

Biocompatibility of small diameter vascular grafts is still problematic due to high activation of platelets and insufficient proliferation of endothelial cells on the artificial surface. As surface properties are crucial for the biological response, we focused on the study of the effects of oxygen and nitrogen plasma treatment on amorphous and semicrystalline poly(ethylene terephthalate), which is commonly used for artificial vascular grafts. Changes in surface morphology after plasma treatment were determined from images taken by atomic force microscopy (AFM), while the change in surface wettability was determined from water contact angle measurements. In vitro biocompatibility of untreated and plasma treated surfaces was determined by studying the proliferation of human umbilical vein endothelial cells (HUVEC) and adhesion of platelets. It was shown that crystallinity of polymers indeed influenced the in vitro biological response as adhesion of platelets was significantly higher on amorphous polymers. Enhanced proliferation of HUVEC was observed on oxygen plasma treated surfaces, while marked differences in the number of activated and attached platelets were observed on nitrogen and oxygen plasma treated surfaces.

► Plasma treatment increased wettability and surface roughness.
► Biocompatibility was significantly influenced by polymer crystallinity.
►  Oxygen plasma treatment enhanced proliferation of endothelial cells.
► Platelets adhesion was controlled by plasma treatment.