The Evaluation on Biological Properties of Carboxymethyl-chitosan and Carboxymethyl-chitin

Carboxymethyl-chitosan and carboxymethyl-chitin were prepared with the methods developed in our laboratory. The DS (degree of substitution) and DD (degree of deacetylation) of the carboxymethyl-chitosan were 103.14% and 97.18% respectively,while the DS of the carboxymethyl-chitin was 96.37%. Their effects on human fibroblasts,intradermal irritation test,in vitro and vivo degradability,and biocompatibility were evaluated. The results indicate that the polysaccharides at low concentrations can facilitate the growth of human fibroblasts and the carboxymethyl-chitosan at 100 μg mL-1 is the most effective. The polysaccharides at higher concentrations,however,inhibit the growth of fibroblasts. The PII (Primary Irritation Index) values of CM-chitosan and CM-chitin are both 0.0,which shows that they have no irritation reaction. Both of the polysaccharides show good degradability and biocompati-bility. Carboxymethyl-chitin degrades faster in vitro than carboxymethyl-chitosan. The latter,however,has no inflammatory reaction after being implanted in vivo for 7 d and shows better biocompatibility. This study may provide a scientific basis for the use of car-boxymethyl-chitosan and carboxymethyl-chitin as biomaterials.