Covalent immobilization of O-butyrylchitosan with a photosensitive hetero-bifunctional crosslinking reagent on biopolymer substrate surface and bloodcompatibility characterization.

O-Butyrylchitosan (OCS) was covalently immobilized onto a substrate (suture and PTFE) surface using the photosensitive hetero-bifunctional crosslinking reagent 4-azidobenzoic acid, which was previously bonded to OCS by the reaction between an acid group of the crosslinking reagent and a free amino group of OCS. The immobilization was accomplished by irradiating the modified OCS coated on the substrate surface with ultraviolet light to photolyze azide groups, thus the crosslinking OCS was immobilized on the substrate surface. The result indicated that OCS molecules immobilized on the substrate, and significantly reduced the fibrinogen adsorption and the deposition and spreading of platelets, demonstrating superior bloodcompatibility. Therefore, OCS could be developed into bloodcompatible biomaterial that used to modify the biomedical devices, such as PTFE and Dacron vascular prostheses surface.