Photoresponsive Multifunctional Nanoplatform Based on ADSC-Exos Coated BPQDs Demonstrates Effective Antibacterial Properties and Induces Macrophage Polarization for Infected Wound Healing.

Bacterial infections and the disturbance of immune microenvironment contribute to chronic non-healing wounds. Macrophage polarization and phenotypic transition play a critical role in modulating the immune microenvironment of wounds. To address these intertwined challenges of bacterial burden and immune dysregulation, an innovative multifunctional therapeutic nanoplatform is developed that integrates black phosphorus quantum dots (BPQDs) into exosomes derived from adipose stem cells (BPQDs@EXOs). In vitro experiments show that the platform exhibited broad-spectrum photothermal antibacterial properties, efficient ROS scavenging ability, and the effect of promoting M2 macrophage polarization. In infected wound models, BE + NIR promotes wound healing by eradicating bacterial infection, attenuating ROS levels, promoting M2 macrophage polarization and accelerating re-epithelialization. Mechanistic insights from deep transcriptomic analyses on day 4 and day 10 confirm that the BE nanoplatform downregulates the expression of proinflammatory genes, upregulates the expression of wound-healing genes, and induces cell proliferation. Overall, this novel approach effectively integrates photothermal antibacterial properties, macrophage polarization regulation and anti-inflammatory effects, thereby creating an optimal immune environment and providing a comprehensive solution to the challenges of non-healing wounds caused by bacterial infections.