Preparation and biological properties of Schiff-base hydrogels crosslinked by benzaldehyde substituted agarose oligosaccharides

Schiff-base hydrogels have gained great attentions in biomedical fields due to their pH-responsive properties. However, oligosaccharide-based hydrogels simply crosslinked by Schiff base bonds have rarely been constructed. Here, we synthesized carboxyl-benzaldehyde substituted agarose oligosaccharide (CBAO) and fabricated CBAO/CMCS hydrogels via the Schiff-base reaction between CBAO and carboxymethyl chitosan (CMCS). The CBAO/CMCS hydrogel could be formed within a few minutes, and the gelation time could be adjusted by the degree of the substitution (DS) and the concentration of the components. Besides the negligible cytotoxicity, the CBAO/CMCS hydrogels showed excellent water retention and pH-sensitive dissociation ability. The antibacterial performance could be improved with increasing acidity, and the highest inhibition rate could be over 60% against both Escherichia coli and Staphylococcus aureus. Moreover, the CBAO/CMCS hydrogel could accelerate the wound healing process and promote the generation of hair follicles in vivo, indicating that the hydrogels would be feasible for wound dressing.