Glycyrrhizic Acid Hydrogel Microparticles Encapsulated with Mesenchymal Stem Cell Exosomes for Wound Healing.

Hydrogel microparticles have been proved to be curative to diabetic wounds. Current trends focus on the integration of bioactive matrix and their smart stimulus-responsive release to meet the complex demand of regeneration in diabetic wound. In this paper, we present novel stem cell exosome-encapsulated Chinese herb glycyrrhizic acid (GA) hydrogel microparticles for wound healing. The integrated GA endows the hydrogel microparticles with antibacterial properties, while the encapsulated exosomes impart them with pro-angiogenesis ability. In addition, as the black phosphorus is incorporated into these hybrid hydrogel microparticles, the release profile of GA and exosomes could be controllable under near-infrared irradiation due to the excellent photothermal effect of black phosphorus and the reversible phase transformation properties of GA. Based on these features, we have demonstrated that these microparticles can effectively kill bacteria, scavenge free radical, and promote angiogenesis from in vitro experiments. Besides, they could also markedly accelerate the wound healing process by down-regulating inflammation and promoting collagen deposition and angiogenesis in bacteria-infected in vivo diabetic wound. These results indicate that the proposed exosome-integrated GA hydrogel microparticles present great potential for clinical diabetic wound treatment.