Surface Heparinization of Polyurethane Via Bromoalkylation of Hard Segment Nitrogens
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- 作者：Ivan S. Alferiev ; Jeanne M. Connolly ; Stanley J. Stachelek ; Allis Ottey ; Lubica Rauova ; and Robert J. Levy
- 刊名：Biomacromolecules
- 出版年：2006
- 出版时间：January 2006
- 年：2006
- 卷：7
- 期：1
- 页码：317 - 322
- 全文大小：110K
- 年卷期：v.7,no.1(January 2006)
- ISSN：1526-4602
文摘
Previous research from our group has demonstrated that bromoalkylation of polyurethane elastomers via basemediated activation of the urethane-hard segment nitrogen groups can be used to either attach bisphosphonategroups to confer calcification resistance or append cholesterol to promote endothelial cell adhesion. In the presentstudies we further explore the potential of this chemical approach by investigating bulk carboxylation ofpolyurethanes via bromoalkylation to enable surface heparinization for thromboresistance. Thus, polyurethane(PU) was modified with pendant 7-carboxy-5-thiaheptyl groups using a polymer-analogous reaction ofbromobutylated PU with tetrabutylammonium 3-mercaptopropionate in mild conditions. The grafting ofpolyallylamine (PAA) onto the surface of carboxylated PU via direct coupling of amino and carboxy groupsresulted in high levels of PAA (up to 8 
g/cm2). The surface-aminated PU was further covalently modified withunfractionated heparin as confirmed by FTIR. Fluorescence labeling of PAA hydrochloride and heparin withBODIPY-FL was used to quantify the extent of surface modifications. Heparin was covalently bound at a highlevel (1.11 ± 0.06 g/cm2) and was shown to be active, with demonstrable Factor Xa inhibition and plateletfactor IV binding. It is concluded that surface amination of bulk-carboxylated PU represents a novel approach forheparinizing PU; carboxylation followed by surface amination represents another important dimension of bromo-alkyl activation of polyurethane hard segments, thereby enabling heparinization.
g/cm2). The surface-aminated PU was further covalently modified withunfractionated heparin as confirmed by FTIR. Fluorescence labeling of PAA hydrochloride and heparin withBODIPY-FL was used to quantify the extent of surface modifications. Heparin was covalently bound at a highlevel (1.11 ± 0.06 g/cm2) and was shown to be active, with demonstrable Factor Xa inhibition and plateletfactor IV binding. It is concluded that surface amination of bulk-carboxylated PU represents a novel approach forheparinizing PU; carboxylation followed by surface amination represents another important dimension of bromo-alkyl activation of polyurethane hard segments, thereby enabling heparinization.