Synthesis and characterization of nitric oxide generative polyrotaxane

L-Arginine was immobilized into a supramolecular-structured polyrotaxane to examine the generation of nitric oxide, with a view to improving antithrombosis and the blood compatibility of polymeric biomaterials. L-Arginine was immobilized to the hydroxyl groups of alpha-cyclodextrins in the polyrotaxane via an ester linkage, and the nitric oxide generation and L-arginine release behavior were characterized. L-Arginine-immobilized polyrotaxane was insoluble in water, but was found to generate nitric oxide when placed in Tris-HCI buffer supplemented with activators. L-Arginine-immobilized polyrotaxane exhibited sustained nitric oxide generation for a period of 250 h. L-Arginine was completely released by non-enzymatic hydrolysis from 200 h to 700 h, with a lag-time for the first 200 h. Consequently, after the generation of nitric oxide and the release of L-arginine from the L-arginine-immobilized polyrotaxane, the residual component will be a polyrotaxane with superior biocompatibility and mechanical properties. These results suggest that L-arginine-immobilized polyrotaxane can be useful in a wide range of medical applications, including use as a nitric oxide generative system for antithrombosis, coating and blending materials of hydrophobic extracorporeal circuits, and implantable catheters.