title: Heparin immobilization by surface amplification.
abstract: A method to increase the amount and improve the bioactivity of heparin (HEP) immobilized on a polymer surface was developed. The surface of polyurethane-urea (PU) coated glass beads was first modified with diisocyanates, followed by surface grafting of polyfunctional polymers (PFP), including: poly(vinyl alcohol), poly(ethyleneimine), and poly(allylamine). The functional groups of the surface grafted PFP (-OH, -NH, or -NH2) were modified with diisocyanates (TDI) to amplify the surface concentration of isocyanate groups, alpha, omega-diamino-terminated polyethylene oxide (PEO; molecular weight, 4,000 daltons) was then coupled to the surface grafted PFP, and the free amino groups were derivatized with TDI. Finally, HEP was coupled to the amplified surface through free -NCO groups of PU-PFP-PEO. The surfaces were quantified during each step of the procedures for -NCO groups and HEP. All grafted surfaces showed a four to eightfold increase in -NCO content and a twofold increase in immobilized HEP content compared with HEP immobilized directly onto the PU surface. The HEP bioactivity tests (including activated partial thromboplastin time, thrombin times, and factor Xa) demonstrated an increased bioactivity of HEP when immobilized through PFP-PEO compared with PFP and PU alone.
authors.affiliation: Department of Pharmaceutics and Pharmaceutical Chemistry, University of Utah, Salt Lake City 84108.
authors.forename: A Z
authors.initials: AZ
authors.lastname: Piao
authors.forename: H A
authors.initials: HA
authors.lastname: Jacobs
authors.forename: K D
authors.initials: KD
authors.lastname: Park
authors.forename: S W
authors.initials: SW
authors.lastname: Kim
mesh_terms: D001672:Biocompatible Materials; D001807:Blood Vessel Prosthesis; D015951:Factor Xa / Q000378:metabolism; D006354:Heart, Artificial; D006493:Heparin / Q000008:administration & dosage*; D006801:Humans; D066298:In Vitro Techniques; D008422:Materials Testing; D010314:Partial Thromboplastin Time; D011108:Polymers; D011140:Polyurethanes; D013499:Surface Properties; D013927:Thrombosis / Q000517:prevention & control
chemical_list: D001672:Biocompatible Materials; D011108:Polymers; D011140:Polyurethanes; D006493:Heparin; D015951:Factor Xa