Surface modification of biomedical grade polyurethane to enable the ordered co-immobilization of two proteins.
Surface modifications of polyurethane (PU)-based implantable materials have the potential to enhance or improve hemo- or cellular-biocompatibility. In general, surface modification methods of PU have included surface treatments, physio-adsorption of desired biomolecules, and the covalent immobilization of reactive or therapeutic biomolecules. When multi-protein immobilizations are desired to mimic the enzymatic reactions found on cells and tissues, it is often necessary to design and develop surface modification strategies that will allow the co-immobilization of proteins. In this study, a surface modification strategy is presented that enables the sequential additional of proteins to a bi-dentate moiety grafted onto the PU surface. The modifications were confirmed via IR and XPS signatures. While the strategy presented is applicable to a wide variety of biomolecules, bovine serum albumin (BSA) and human immunoglobulin (hIgG) were selected as model proteins. A total immobilized protein density of 0.298 ± 0.037 μg/cm² was obtained, with nearly equal amounts of protein on each arm of the bi-dentate moiety. Proteins immobilizations were also visualized with immunofluorescent staining. Finally, the method proposed in this study was used to demonstrate a significant increase (P < 0.05) in the catalytic conversion of protein C (PC) to activated PC (APC) using sequentially immobilized thrombomodulin (TM) and endothelial PC receptor (EPCR) as compared to the two proteins immobilized onto a surface in random order.
Department of Chemical and Biomolecular Engineering, University of Nebraska, Lincoln, 207 Othmer Hall, Lincoln, NE 68588-0643, USA.
Karl E
KE
Kador
Anuradha
A
Subramanian
D000818:Animals; D001672:Biocompatible Materials / Q000737:chemistry*; D002417:Cattle; D006801:Humans; D055767:Immobilized Proteins / Q000737:chemistry*; D007074:Immunoglobulin G / Q000737:chemistry; D011140:Polyurethanes / Q000737:chemistry*; D012710:Serum Albumin, Bovine / Q000737:chemistry; D013499:Surface Properties
D001672:Biocompatible Materials; D055767:Immobilized Proteins; D007074:Immunoglobulin G; D011140:Polyurethanes; D012710:Serum Albumin, Bovine