Synthesis of novel chitosan with chitosan side chains

Although extensive research is in progress on the use of chitin and chitosan, poor solubility has been one of the main obstacles to their effective utilization. Introduction of carbohydrate branches into chitin and chitosans gave branched polysaccharide analogs, which showed good water solubility and induced new chemical and biological functions. In this study, hyperbranched chitosan derivatives were synthesized by introducing chitosan branches to the amino group of chitosan by the reductive N-alkylation method. Compared with the linear chitosan, the hyperbranched derivatives exhibited improved water solubility in the physiological conditions (pH 6.8). Although the viscosity of starting chitosans for main chain increased with the increase in their weight average molecular weights (80–190 kDa), the corresponding hyperbranched chitosan derivatives showed relatively low viscosities.