Surface biocompatible modification of polyurethane by entrapment of a macromolecular modifier

A macromolecular biocompatible surface modifier for polyurethane (PU), namely, polyurethane-block-poly(vinylpyrrolidone) (PU-b-PVP) copolymer, was synthesized by coupling hydroxyl-terminated PVP with diisocyanate-terminated poly(ethylene glycol) using 1,6-hexamethylene diisocyanate (HDI) as coupling agent. The chemical structure and molecular weight of the synthesized copolymer were systematically characterized by nuclear magnetic resonance spectrum ((1)H NMR), Fourier transform infrared spectroscopy (FTIR) and gel permeation chromatography (GPC). The synthesized surface modifier was blended with PU and effectively increased the hydrophilicity of PU. To evaluate the hemocompatibility of the PU/PU-b-PVP blend films, the extent of platelet adsorption, plasma recalcification time and hemolysis were measured. To determine if the blend films were toxic to mammalian cells, viability of the cells cultured on the blend films was assayed. All results indicated that the blood and cell compatibilities of the PU films were improved significantly after entrapment of a few PU-b-PVP copolymers into PU.