SURFACE CARBOXYMETHYLATION OF A CHITIN HYDROGEL

A chitin hydrogel was modified to give a bilayer structure comprised o f a surface layer of carboxymethyl-chitin and bulk chitin within. By g radually increasing the sodium hydroxide concentration used in the act ivation step of the reaction, thickness of the carboxymethyl layer wit h accompanying swellability was varied. These bilayer hydrogels showed distinct morphological differences between the surface and bulk regio ns, visualized with a basic dye test and verified by FT-IR. Carboxymet hylation was found to increase the lysozyme susceptibility of these hy drogels. These modified hydrogels have potential in orthopedics applic ations where enhanced water swellability and calcium affinity imparted by surface carboxymethylation are desirable properties.