Surface functionalization of polyurethane for the immobilization of bioactive moieties on tissue scaffolds

Segmented polyurethanes are widely used in medical devices because of their desirable physical and chemical properties and proven biocompatibility. While polyurethane is in many respects an ideal tissue scaffold, its performance is no better than other synthetic polymers, which is due in part to its surface properties. Here, we describe a method for the functionalization of polyurethane scaffolds that involves physically incorporating another polymer (poly(ethyleneimine)) such that the surface integrity and bulk properties are retained; the primary amine groups thus incorporated into the polyurethane surface enable subsequent coupling with dextran and recombinant peptides by means of reductive amination. The efficacy of the surface functionalization of a medical grade aliphatic poly(ether)urethane is verified by surface analysis (secondary ion mass spectrometry) and fluorescence and spectrophotometric assays adapted specifically for this purpose. Further assessment of the surfaces by direct cell contact and analysis of the cellular response in terms of cell coverage and morphology before and after modification with the specific peptide sequences GRGDSPK and recombinant Fibrillin-1 fragment PF9