Yasuharu Noishiki

Chitin and Chitosan for use as a Novel Biomedical Material

Chitin [a (l→4)-linked 2-acetamido-2-deoxy-β-D-glucan], and chitosan (its N-deacetylated compound) were usable as a novel biomedical material: (1) N-Acetylated hybrid gels of chitosan and collagen were transparent and elastic. The lyophilized gels adsorbed rabbit blood or distilled water (up to 20 mL/g). (2) A segment of polyester polyfilament suture coated with a thin material to be examined was directly inserted into the lumen of dog’s peripheral veins, and the in vivo blood compatibility was macroscopically determined from the blood coagulum formed on the suture surface, indicating that chitosan was thrombogenic, and N-fatty acyl (C6-C12) chitosans, and N-acetylated hybrids of chitosan and collagen were nonthrombogenic. (3) The anticoagulant activity [units/ mg] was in the sequence: O-sulfated N-acetylchitosan [331–379]> N,O-sulfated chitosan [190–280]. heparin [174]. sulfated O-carboxymethyl-chitosan [27–31] with respect to activated partial thromboplastin time. (4) The lipolytic activity (meg/L) was in the sequence: N,O-sulfated chitosan [3200] heparin [950]. sulfated O-carboxymethylchitosan [300]. O-sulfated N-acetylchitosan [100] with respect to lipoprotein lipase.