M2 macrophage-derived exosome-encapsulated microneedles with mild photothermal therapy for accelerated diabetic wound healing

Due to local overactive inflammatory response and impaired angiogenesis, current treatments for diabetic wounds remain unsatisfactory. M2 macrophage-derived exosomes (MEs) have shown considerable potential in biomedical applications, especially since they have anti-inflammatory properties that modulate macrophage phenotypes. However, exosome-based strategies still have limitations, such as short half-lives and instability. Herein, we develop a double-layer microneedle-based wound dressing system (MEs@PMN) by encapsulating MEs in the needle tips and polydopamine (PDA) nanoparticles in backing layer to simultaneously suppress inflammation and improve angiogenesis at the wound site.