High purity Chitosan is extracted from Chitin. DDA: degree of deacetylation; cP: centipoise for dynamic viscosity. Chitosan has NH2 groups that can be used for bioconjugation or further derivatization using amide coupling reaction with carboxylic acid. Chitosan is not soluble in water but very soluble in 0.1% acetic acid due to the protonation of the amino groups leading to positively charged ammonium groups, which may be used in both amine bioconjugation or electrostatic interactions with negatively charged polymers or surfaces.
Chitosan is produced by deacetylation of chitin, which is the structural element in the exoskeleton of crustaceans (such as crabs and shrimp) and cell walls of fungi. The degree of deacetylation (%DD) can be determined by NMR spectroscopy from 60 to 100%.Chitosan products are characterized by either its MW or its viscosity. The amino group in chitosan has a pKa value of ~6.5.
1) Preparation and Characterization of Chitin and Chitosan A Review, Journal of Aquatic Food Product Technology, 1995, 4(2): 27-52