Multifunctional Carbon Quantum Dots for Monitoring and Therapy of Bacterial Infected Wounds.

Bacterial infections in wounds and bacteremia present significant global health challenges, driving the urgent need for innovative alternatives to traditional antibiotics. Here, the development of PEI-EDTA-2Na carbon quantum dots (PECDs) synthesized via a hydrothermal method is reported. Synthesis conditions affect PECDs' antibacterial efficacy; those at 180 °C have optimal -NH₂ functionalization for better adhesion and activity. PECDs are pH - responsive, eradicating bacteria in weakly acidic conditions by disrupting DNA and proteins. Following the resolution of infection, PECDs adapt to neutral and alkaline environments, where they scavenge reactive oxygen species (ROS), reduce inflammation, promote macrophage polarization, and accelerate wound healing. Furthermore, PECDs significantly improve survival in bacteremia models. Their intrinsic fluorescence enables real-time pH monitoring of wounds, offering a non-invasive diagnostic tool. Genomic and transcriptomic analyses reveal that PECDs disrupt bacterial metabolism and resistance pathways, while simultaneously supporting antibacterial and anti-inflammatory responses during tissue repair. This dual functionality-combining therapeutic efficacy in wound healing with antimicrobial and anti-inflammatory properties in bacteremia-positions PECDs as a versatile platform for smart wound management and an emerging candidate for advanced biomedical applications.