Bioactive heparin surfaces from derivatization of polyacrylamide-grafted LLDPE

Primary amine groups were introduced into polyacrylamide-LLDPE films, using the Hofmann degradation synthesis. The Hofmann degradation was studied at room temperature using sodium hypochlorite and sodium hydroxide at different concentrations. Diazotized heparin was covalently bound to the grafted LLDPE film via the primary amine groups. Surfaces were analysed with ESCA, ATR-IR, chloride titration and Toluidine Blue. Evaluation of the biological activity of the heparinized surfaces was made by measuring the capacity for binding antithrombin (AT) and inhibition of the activated coagulation factor XII (FXIIa). The heparinized surfaces were able to bind up to 3 pmol cm-2 of AT in solution with ionic strengths of I = 0.15 and I = 0.40. No activation of the adsorbed FXII was detected.