Platelet adhesion to novel phospholipid materials: Modified phosphatidylcholine covalently immobilized to silica, polypropylene, and PTFE materials

Abstract

Based on the premise of achieving blood compatibility through mimicking the chemical constitutents of the biologically insert surface of the unactivated platelet membrane, a process was developed that entails the covalent grafting of modified phosphatidylcholine molecules to materials including silica, polypropylene, and polytetrafluoroethylene (PTFE) polymer films. These materials were characterized using x-ray photoelectron spectroscopy (XPS) and contactangle measurements. The phosphatidylcholine-containing materials (PC materials) were used as substrates in the plateletadhesion assays and were subjected to enzymatic degradation evaluation. Phosphatidylcholine-grafted silica materials do not support platelet adhesion. In addition the number of adherent platelets correlate with the amount of grafted phospholipid present, as indicated by the phosphorus/ carbon ratio obtained by XPS analysis. Platelet adhesion to phosphatidylcholine-grafted polypropylene and PTFE was inhibited 80% and 90%, respectively, when compared with platelet adhesion to unmodified polypropylene and PTFE.