Polydopamine Nanoparticle-Integrated Smart Polysaccharide Hydrogel: Photothermal-Triggered CO Release for Diabetic Wound Microenvironment Modulation.

PURPOSE

Bacterial infection, oxidative stress, vascular damage, and nutrient deficiencies significantly hinder the repair of diabetic skin wounds. Conventional wound dressings offer limited protection and fail to effectively promote the healing of diabetic wounds. To address these challenges, we developed a photothermal-responsive polysaccharide hydrogel capable of releasing carbon dioxide (CO@PDA Hydrogel).

METHODS

This hydrogel utilizes carboxymethylated polysaccharide as the primary matrix, cross-linked through metal coordination bonds, and incorporates bicarbonate-containing polydopamine nanoparticles (CO@PDA NPs) with photothermal conversion properties to generate CO. The structure and morphology of CO@PDA NPs were characterized by DLS, SEM, FTIR, and XRD, and the hydrogel properties of CO@PDA Hydrogel were characterized by SEM, rheological properties, and FTIR. The photothermal properties of the CO@PDA Hydrogel were studied by measuring the temperature change and CO release after irradiation with an NIR laser (808nm). The improvement effect of CO@PDA Hydrogel on the diabetes wound microenvironment was comprehensively evaluated by promoting L929 cell proliferation, inhibiting bacterial growth ( and ), and treating diabetes wound infection in rat models.

RESULTS

Under 808 nm near-infrared laser irradiation, the embedded CO@PDA NPs convert light into heat, triggering the decomposition of HCO and releasing a substantial amount of CO locally at the diabetic wound site. The released CO responds to the Bohr effect, alleviating hypoxia and promoting angiogenesis. Simultaneously, the polysaccharide in the hydrogel exerts antioxidant and anti-inflammatory effects, while the cross-linking agent Fe and the photothermal properties of CO@PDA NPs provide robust antibacterial activity.

CONCLUSION

The self-assembled cross-linked carboxymethyl polysaccharide Hydrogel with CO@PDA NPs prepared in this study has a good photothermal conversion effect. It improves the microenvironment of diabetes wounds by improving hypoxia, antibacterial, antioxidant, and other effects, providing a good multi-functional alternative material for the treatment of refractory diabetes wounds.