Design of novel sheet-shaped chitosan hydrogel for wound healing: a hybrid biomaterial consisting of both PEG-grafted chitosan and crosslinkable polymeric micelles acting as drug containers.

In this study, we successfully prepared a novel "sheet-shaped" chitosan hydrogel for wound healing consisting of both PEG-g-chitosan and a crosslinkable polymeric micelle. The study's findings clarify that the PEG modification percentage (PMP) of PEG-g-chitosan increased proportionally as the weight ratio of PEG/chitosan increased. Furthermore, the positive second virial coefficient of PEG-g-chitosans from a Debye plot strongly suggests that the PEG modification greatly improved the solubility of the water-insoluble chitosan. Finally, the "sheet-shaped" "flexible" hydrogel formed by mixing solutions containing either PEG-g-chitosan with moderate PMP or polymeric micelles exhibited the highest storage modulus. The sheet itself exhibited an attractive feature insofar as polymeric micelles, which can act as drug containers facilitating the incorporation and the gradual release of drugs, are covalently immobilized in the polymeric network of the hydrogel. The results obtained in the present study show that the hybrid PEG-g-chitosan hydrogel containing crosslinkable polymeric micelles has the potential to address the need for novel functional biomaterials.