Study on the repair effect of photothermal hydrogel with controllable adhesiveness regulated by melanin and magnesium ions on diabetic wounds.

Chronic non-healing wounds, characterized by prolonged disease duration and low compromised reparative potential, not only cause patients to suffer from persistent physical pain and impaired daily living ability, but also are prone to inducing severe complications such as infection and amputation, posing a serious threat to patients' health and quality of life. In this study, a melanin derivative (M-HPCS) with excellent photothermal properties was successfully prepared through the condensation reaction between natural squid melanin and a chitosan derivative (HPCS). Subsequently, by virtue of charge interaction, M-HPCS was assembled with a hyaluronic acid derivative (HA-PEG) to construct a photothermal hydrogel (M-HPCS/HA-PEG) with controllable adhesion performance. This hydrogel could further enhance its own adhesion capacity by chelating magnesium ions, making it suitable for the repair and treatment of non-healing wounds. The results demonstrated that, relying on the dual regulatory effect of sepia melanin and Mg2+, the hydrogel could achieve controllable adhesion to the wound and non-invasive detachment after use. The combination therapy of hydrogel and photothermal treatment exhibited the optimal repair efficacy by effectively regulating the inflammatory level in the microenvironment of chronic non-healing wounds, promoting angiogenesis, accelerating the epithelialization process, and thereby significantly facilitating wound healing. The photothermal hydrogel possessed ideal adhesion adaptability to different types of wounds and could effectively promote wound repair through hyperthermia. This study provides novel insights and technical support for the clinical treatment of chronic non-healing wounds.