Rheology of Chitosan and Genipin Solutions

This paper investigates the rheological behaviour of chitosan solutions crosslinked with different concentrations of genipin at body temperature and physiological pH. The effect of the crosslinker concentration on the rheological properties of hydrogels was evaluated. The oscillatory time sweep was used to analyze the dynamics of G’ during in situ gelation experiments enabling the determination of the gelation time. Additionally, the stress and frequency sweeps were employed to measure G’ of cured hydrogels. The solutions of chitosan crosslinked with genipin at physiological conditions were found to form relatively strong elastic gels for all the concentrations, when compared to pure chitosan. A significant reduction on gelation time was achieved. This behaviour shows that these formulations are able to be produced in situ and thus constitute promising matrices for cells and bioactive molecules encapsulation.