Surface modification of polycaprolactone membrane via layer-by-layer deposition for promoting blood compatibility.

The polycaprolactone (PCL) membranes were successfully modified by deposition of chitosan/heparin multilayer via a simple electrostatic self-assembly method. To immobilize chitosan, a novel ternary polysaccharide derivate, chitosan-g-PCL-b-poly-(ethylene glycol) (PEG) was used coating on PCL film first, which resulted in the presence of positive charges onto PCL surface as the basis for following electrostatic self-assembly. The process of modification was monitored by X-ray photoelectron spectroscopy, static contact angle measurement, and atomic force microscopy. The chitosan-g-PCL-b-PEG/heparin complex immobilized on PCL surface presented it with increasing hydrophilicity and microphase separation structure. Then in vitro hemocompability experiments indicated that this multilayer deposition on PCL resisted the platelets adhesion and prolonged the plasma recalcification time effectively, relative to the untreated PCL. Such chitosan-g-PCL-b-PEG/heparin-modified PCL may have good potential for use in vascular tissue engineering.