Surface modification of biomedical grade polyurethane to enable the ordered co-immobilization of two proteins

Karl E. Kador, Anuradha Subramanian

Research output: Contribution to journalArticlepeer-review

4 Scopus citations


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.

Original languageEnglish (US)
Pages (from-to)1983-1999
Number of pages17
JournalJournal of Biomaterials Science, Polymer Edition
Issue number15
StatePublished - 2011


  • Co-immobilization
  • polyurethane

ASJC Scopus subject areas

  • Biophysics
  • Bioengineering
  • Biomaterials
  • Biomedical Engineering


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