Chitosan-HOBt water based system : an effective pathway for chitosan conjugating reaction and for aerogel formation

Abstract

The present work proposes chitosan-hydroxybenzotriazole (HOBt) water-based system to prepare chitosan conjugated with amino acids which are ideal drug targeting functional groups. The conjugation is demonstrated based on the use of chitosan nanoscaffold prepared from deacetylation of chitin whisker. The conjugation with asparagines and tryptophan is accomplished by using WSC. The qualitative and quantitative analyses confirm the degree of substitution to be 25% and 4% for asparagines and tryptophan, respectively. By simple freeze drying, both derivatives give cotton-like scaffold. The work extends to study chitosan nanocomposite aerogel by using chitosan-HOBt water-based system. The dicarboxylated polyethylene glycol shows effective crosslinking reaction as evidenced from the hydrogel formation. The water exclusion by freeze-drying gives aerogel.