Autoclaving-Triggered Hydrogelation of Chitosan-Gluconic acid Conjugate Aqueous Solution for Wound Healing

Moist wound healing is known to heal wounds faster than dry wound healing. Hydrogel wound dressings are suitable for moist wound healing because of their hyperhydrous structure. Chitosan, a natural polymer, promotes wound healing by stimulating inflammatory cells and releasing bioactive compounds. Therefore, chitosan hydrogel has great potential as a wound dressing. In our previous study, physically crosslinked chitosan hydrogels were successfully prepared solely by freeze-thawing of chitosan-gluconic acid conjugate (CG) aqueous solution without using any toxic additives. Furthermore, the CG hydrogels could be sterilized by autoclaving (steam sterilization). In this study, we showed that autoclaving (121 °C, 20 min) of a CG aqueous solution simultaneously achieved gelation of the solution and sterilization of the hydrogel. Hydrogelation of CG aqueous solution by autoclaving is also physically crosslinking without any toxic additives. Further, we showed that the CG hydrogels retained favorable biological properties of the CG hydrogels prepared by freeze-thawing and subsequent autoclaving. These results indicated that CG hydrogels prepared by autoclaving were promising as wound dressings.