Anti-platelet adhesion and in situ capture of circulating endothelial progenitor cells on ePTFE surface modified with poly(2-methacryloyloxyethyl phosphorylcholine) (PMPC) and hemocompatible peptide 1 (HCP-1)

Abstract

We recently reported in vitro suppression of platelet adhesion on expanded polytetrafluoroethylene (ePTFE) by surface grafting of poly(2-methacryloyloxyethyl phosphorylcholine) (PMPC). However, this may be inadequate for long-term hemocompatibility of blood-contacting biomaterials, and it has led us to develop a strategy of circulating mononuclear cell-capture. ePTFE was treated with argon (Ar) plasma, and grafted with 2-methacryloyloxyethyl phosphorylcholine (MPC) and methacrylic acid (MAA), by glycidyl methacrylate (GMA)-anchored graft polymerization. Next, it was immobilized with integrin α4β1-positive circulating blood cell-specific peptides, i.e., the traditional arginine-glutamic acid-aspartic acid-valine (REDV), and our original hemocompatible peptide-1 (HCP-1). Both the surfaces retained the anti-platelet property just like the PMPC-grafted surface, and revealed considerable affinity to human umbilical vein endothelial cells (HUVEC), which is a well-known in vitro integrin α4β1-positive model. Better HUVEC spreading and proliferation was also confirmed, in terms of the cell extension property. Since coagulation and endothelialization on the materials compete in the body, they cannot be properly evaluated separately, in vitro. They were assessed by using an in situ porcine closed-circuit system for 18 h in the present study. Our findings suggest that poly(MPC-co-MAA) is a great ePTFE surface modifier, exhibiting good hemocompatibility in association with REDV/HCP-1 immobilization, which suppresses anti-platelet adhesion and enhances circulating cell capture simultaneously.