Biobased pH-responsive and self-healing hydrogels prepared from O-carboxymethyl chitosan and a 3-dimensional dynamer as cartilage engineering scaffold.

Novel dynamic hydrogels were prepared from O-carboxymethyl chitosan (CMCS) and a water soluble dynamer Dy via crosslinking by imine bond formation using an environmentally friendly method. Dy was synthesized by reaction of Benzene-1,3,5-tricarbaldehyde with Jeffamine. The resulting soft hydrogels exhibit a porous and interconnected morphology, storage modulus up to 1400 Pa, and excellent pH-sensitive swelling properties. The swelling ratio is relatively low at acidic pH due to electrostatic attraction, and becomes exceptionally high up to 7000 % at pH 8 due to electrostatic repulsion. Moreover, hydrogels present outstanding self-healing properties as evidenced by closure of split pieces and rheological measurements. This study opens up a new horizon in the preparation of dynamic hydrogels with great potential for applications in drug delivery, wound dressing, and in particular in tissue engineering as the hydrogels present excellent cytocompatibility.