Construction and hemocompatibility study of highly bioactive heparin-functionalized surface.

A simple method is developed to construct anticoagulant surfaces via passive adsorption of heparin onto the protonated plasma-polymerized allylamine (PPAam) films from phosphate-buffered saline (PBS). These protonated PPAam surfaces are found to have high affinity to heparin. Importantly, the heparin-functionalized PPAam (Hep-PPAam) surfaces show good retention of heparin after long-term immersion in PBS. The Hep-PPAam surface prolongs the activated partial thromboplastin time for about 20 s as compared to 316L stainless steel even though the adsorption amount of heparin is only about 300 ng/cm(2). This indicates that the heparin bound to the protonated PPAam surfaces in this way maintains a high bioactivity. Blood platelet adhesion and activation on this surface is remarkably reduced and adsorption and activation of fibrinogen is inhibited. Thus, Hep-PPAam surface modification leads to a significant improve of the hemocompatibility.