Preparation and characterization of a poly(2-hydroxyethyl methacrylate) biomedical hydrogel

Heparin a commonly used anticoagulant was immobilized onto a poly(2-hydroxyethyl methacrylate) hydrogel using glutaraldehyde as a coupling agent in a heterogeneous and homogeneous phase. The amount of immobilized heparin was determined using a colorimetric assay. The thrombogenicity of the gels was assessed using modified activated partial thromboplastin time (aPTT) and thrombin time (TT) tests. Statistically significant differences in both TT and aPTT were observed between the heparinized gels and the non-modified gels (i.e. controls). Antithrombogenic activity was still observed on the gels even after three weeks rinsing where all the non-immobilized heparin was deemed to have leached out of the gel. Thus the significant residual heparin like activity was attributed to the immobilization of heparin in its bioactive form.