Heparin as a molecular spacer immobilized on microspheres to improve blood compatibility in hemoperfusion.

Heparin, a highly sulfated linear polysaccharide, with anticoagulation function and blood compatibility is widely used as a biomaterials in medical application, but the most importance of heparin is its structure function as the macromolecular space arm. In this study, heparin as a spacer was covalently immobilized on the chloromethylated polystyrene microspheres (Ps) and then connected with l-phenylalanine forming the Ps-Hep-Phe structure, which was developed for endotoxin adsorption in hemoperfusion. The grafting density of heparin reach the maximum when the initial concentration of heparin solution was 5 mg/mL. The adsorbents with the heparin as a spacer showed the prolonged clotting times, low protein adsorption, and reduced the hemolysis rate, indicating that heparin-modified adsorbents have great blood compatibility. The adsorption capacity of Ps-Hep-Phe for endotoxin was 25.15 EU/g in dynamic adsorption, higher than that of Ps. Therefore, this study imply that heparin would be promising for modification of adsorbents in hemoperfusion.