Mild Heat Stimulating and Microenvironment Reprogramming Hydrogel for Accelerating Diabetic Wound Healing

Diabetic wounds are characterized by persistent hyperglycemia, excessive ROS accumulation, sustained inflammation, and impaired angiogenesis, yet current treatments remain suboptimal. To address these challenges, we developed a mild heat stimulating and microenvironment reprogramming hydrogel (termed C-4-N) via a green synthetic strategy. L-Arginine (L-Arg) triggered the spontaneous self-polymerization of protocatechuic aldehyde (PA) into poly (protocatechuic aldehyde) (PPA) nanoparticles, onto which ginsenoside Compound K (CK) was subsequently loaded, yielding CK/L-Arg/PPA nanoparticles. These nanoparticles were then uniformly embedded into a dynamic disulfide network composed of α-lipoic acid (LA)-modified chitosan (CS-LA) and 4-arm-PEG-SH under UV irradiation without toxic photo-initiators, forming the C-4-N hydrogel. The C-4-N hydrogel reprogrammed the diabetic wound microenvironment through three synergistic mechanisms, lowering blood glucose and scavenging ROS via the coordinated actions of LA, CK and PPA, promoting M1-to-M2 macrophage polarization via downregulation of pro-inflammatory cytokines (TNF-α, IL-6) and upregulation of anti-inflammatory cytokines (IL-10, TGF-β1), further amplified by mild photothermal stimulation of 40-43 °C. In a diabetic rat model, the C-4-N hydrogel achieved a near-complete wound closure rate of 99.49 ± 0.10% on day 13 upon mild photothermal stimulation, accompanied by enhanced re-epithelialization, organized collagen deposition, vascular maturation, and systemic glucose regulation. In summary, this green synthesized, mild heat-stimulating hydrogel establishes a synergistic microenvironment reprogramming paradigm for chronic diabetic wound managements.