Tunable adhesive hydrogel enhances diabetic wound closure through bacterial inactivation and immune microenvironment modulation.

Diabetic wound healing remains a complex scientific challenge due to the extremely complex microenvironment, including sustained hypoxia, high levels of reactive oxygen species (ROS), repeated bacterial infection, and abnormal immune regulation. Herein, a tunable adhesive hydrogel (PTA@Hydrogel) is constructed that regulates the immune microenvironment to accelerate diabetic wound healing. ε-Polylysine (EPL) was cross-linked with N-isopropylacrylamide (NIPAM), polydopamine (PDA) coated microalgae system (PTA), and α-lipoic acid sodium (LA-Na) under 365 nm irradiation to fabricate PTA@Hydrogel. PTA@Hydrogel exhibits photothermal tunable adhesive and could benignly peel off from the skin under NIR irradiation. PTA@Hydrogel could continuous release oxygen, eliminate bacteria and its biofilms, scavenge ROS, relieve lipopolysaccharide (LPS)/iron-overload induced cells' oxidative damage. Furthermore, PTA@Hydrogel could enhance M2-type macrophage polarization. In vivo studies reveal that this hydrogel could eliminate bacteria infection, inhibit inflammation, and promote vessel regeneration and collagen deposition, thereby accelerating diabetic wounds healing. This multifunctional hydrogel shows a promising concept and an alternative therapeutic strategy for treating bacteria-infected diabetic wounds.