Dual-crosslinked, self-healing and thermo-responsive methylcellulose/chitosan oligomer copolymer hydrogels.

Self-healing, thermo-responsive hydrogels have received increasing attention for tissue engineering, drug delivery, and cosmetic applications. Here, a thermo-responsive hydrogel with self-healing properties was prepared from methylcellulose (MC) and a water-soluble chitosan oligomer (CHI-O). First, dialdehyde methylcellulose (DAMC) derivative was synthesized from MC via periodate oxidation, and its rheological behavior was investigated according to the degree of oxidation. Next, dual-crosslinked DAMC/CHI-O copolymer hydrogels were obtained via Schiff base formation between the aldehyde group of DAMC and the amino group of CHI-O. These hydrogels were chemically linked by imine bonds and physically linked through hydrophobic interactions originating from MC. Based on rheological and compression tests, the gelation rate, mechanical properties, and self-healing properties of the copolymer hydrogels are compared with those of the MC hydrogel. Finally, the release of model compounds (adenosine and l-ascorbic acid) from the DAMC/CHI-O copolymer hydrogel was studied as a preliminary test for cosmetic applications.