Anticoagulant surface coating using composite polysaccharides with embedded heparin-releasing mesoporous silica

Release of heparin from the surface of biomaterials is a feasible and efficient manner for preventing blood coagulation because of the high bioactivity of free heparin and a low application dosage compared to intravenous injection of heparin. Here we report a novel method featuring a blend of heparin-loaded SBA-15, catechol-modified chitosan (CCS), and heparin as a heparin-releasing film. The release of heparin was based on its leakage from heparin-loaded amino-functionalized mesoporous silica SBA-15 (SBA-15-NH2), which was controlled by the amino density of the SBA-15-NH2. Heparin-loaded SBA-15-NH2, CCS, and heparin were mixed together, and the mixture was cast onto the surface of a polydopamine-modified substrate, forming a heparin-releasing film on the surface of the substrate. The polydopamine acted as an adhesive interlayer that stabilized the film coated on the substrate. The sustained release rates of heparin from the film ranged from 15.8 to 2.1 μg/cm(2)/h within 8 h. The heparin-releasing film showed low fibrinogen adsorption, platelet adhesion, and hemolysis rate, indicating that it has good blood compatibility. This new approach would be very useful for modifying the surface of versatile blood-contacting biomaterials and ultimately improve their anticoagulation performance.