Surface carboxymethylation of a chitin hydrogel

Abstract

A chitin hydrogel was modified to give a bilayer structure comprised of a surface layer of carboxymethyl-chitin and bulk chitin within. By gradually increasing the sodium hydroxide concentration used in the activation step of the reaction, thickness of the carboxymethyl layer with accompanying swellability was varied. These bilayer hydrogels showed distinct morphological differences between the surface and bulk regions, visualized with a basic dye test and verified by FT-IR. Carboxymethylation was found to increase the lysozyme susceptibility of these hydrogels. These modified hydrogels have potential in orthopedics applications where enhanced water swellability and calcium affinity imparted by surface carboxymethylation are desirable properties.