Abstract 336: Reactive Ion Surface Modification of Vascular Graft Materials Enhances Endothelialization Without Promoting Thrombosis

Abstract

Previous work demonstrated that poly(vinyl alcohol) (PVA) holds great potential as a cardiovascular biomaterial. PVA prevents thrombosis at least as well as expanded polytetrafluoroethylene (ePTFE) clinical vascular grafts in whole blood studies. However, long term in vivo success of this material will likely depend on its ability to support an endothelial cell (EC) monolayer. To promote EC attachment and growth we are treating the PVA surface with high energy reactive ions. We hypothesize that increasing the concentration of reactive groups on the surface of the PVA will increase endothelial outgrowth cell (EOC, a type of endothelial progenitor cell isolated from whole blood) attachment without increasing thrombosis. To test this hypothesis we exposed PVA films to reactive ion modifications using O 2 , N 2 , and Ar gases at a variety of powers and durations. Treated samples were then characterized with X-ray photoelectron spectroscopy to quantify surface chemistries. Samples were seeded with EOCs to quantify attachment and proliferation using immunohistochemistry. Platelet and fibrin accumulation was measured dynamically in PVA tubes using a baboon arteriovenous shunt with radiolabeled platelets for 1hr. Flow rate was controlled and no anticoagulants were given. O 2 and N 2 treatments encouraged cell adhesion on the PVA films in an energy dependent manner, which correlated to an increase in surface nitrogen. Initial shunt data (n=3) indicate that treated samples did not have increased platelet attachment compared to untreated PVA or ePTFE. In conclusion, reactive ion modified-PVA demonstrates a promising biomaterial by supporting EC growth without increasing thrombosis.