Photothermal Microneedle Hydrogel Patch for Refractory Soft Tissue Injuries through Thermosensitized Anti-Inflammaging Modulation

Soft tissue injuries (STIs) are the most common cause of extremity pain and motion dysfunction. Persistent inflammatory activation of immune cells characterized by senescence-associated secretory phenotype (SASP) and mitochondrial stress are considered the primary causes of STIs, a pathological process also termed inflammaging. Meanwhile, scavenging excessive “cellular waste” in the inflammaging microenvironment and further activating tissue repair processes remain elusive. Herein, an anti-inflammaging photothermal hydrogel microneedle patch for treating STIs is developed. Taurine-loaded Prussian blue nanoparticles (Taurine@PB) are encapsulated in a methacrylate-based hyaluronic acid hydrogel (HAMA) and further fabricated into taurine@PB@HAMA@microneedles (TPH@MN) patches. The acidic microenvironment of chronic inflammation and mild photothermal effects promote taurine release and anti-inflammaging immunomodulation, inhibiting mitochondrial stress via the SIRT3-NF-κB axis to promote glycolytic metabolic microenvironment of neutrophils reprogramming toward oxidative phosphorylation metabolism. Furthermore, TPH@MN activates macrophage efferocytosis and initiates the process of tissue repair. In mouse models of chronic diabetic wounds and tibialis anterior (TA) muscle injury, TPH@MN inhibits SASP expression and promotes STIs healing through thermosensitized anti-inflammaging immunomodulation. In summary, TPH@MN circumvents the side effects of systemic administration, providing new translatable options in the treatment modalities for patients suffering from STIs worldwide.