Dynamic hydrogel-integrated microneedle patch with extracellular vesicles encapsulation for wound healing

Excessive reactive oxygen species (ROS) generated by wounds and bacterial infection are the great obstacles for diabetic wound closure. Here, we present a novel dual ROS-scavenging and antibacterial microneedle array patch with M2 macrophage-derived extracellular vesicles (M2-EVs) encapsulation for diabetic wound healing. The microneedle patch with a core–shell structure is composed of hyaluronic acid (HA) and PFP hydrogel crosslinked by polyvinyl alcohol (PVA)/2-formylphenylboronic acid (2-FPBA)/polyetherimide (PEI). When exposed to high levels of ROS existed in the wound, the dynamic covalent bonds of the hydrogel network can dissociate and subsequently release M2-EVs from the HA core. Benefitting from ROS-scavenging properties, antibacterial activities, and macrophage polarization driven by M2-EVs, the microneedle patch could effectively promote wound closure in diabetic animal models. These results indicated that the proposed ROS-scavenging microneedle patches with EVs delivery are promising for variety of difficult-to-heal wounds in clinical application.