Effect of stoichiometry and pH on the structure and properties of Chitosan/Chondroitin sulfate complexes

This work reports the formation of chitosan (CHT)/chondroitin sulfate (CS) polyelectrolyte complexes and evaluates the changes in their complexation-stoichiometries, crystallinity, and mechanical properties at different pHs used for both complex preparation and swelling. Through high-performance liquid chromatography, the changes in CHT/CS complex stoichiometry due to CS release from CHT/CS complexes, which occurred mainly during swelling at pH a parts per thousand yen6, were determined. In addition, strong evidences of self-assembling on CHT/CS complex network as swelled at pH 12 buffer were observed by WAXS patterns. Such a new rearrangement of the network increases the CHT/CS complexes rigidity as well as their elastic moduli, E, as observed through compressive tests. The results found in this work provide new information to allow the tailoring of the biofunctionalities of the CHT/CS complex for the development of physiological pH-compatible materials.