Carbon dots-releasing hydrogels with antibacterial activity, high biocompatibility, and fluorescence performance as candidate materials for wound healing

Antibacterial hydrogels have received attention for preventing infections and for their biomedical applications. However, traditional antibiotics-containing and metal nanoparticle-containing hydrogels often cause bacterial resistance, exhibit low biocompatibility, and lack real-time monitoring capability. Here, a fluorescent antibacterial hydrogel with antibacterial ability, excellent optical performance, and high biocompatibility was developed based on cationic carbon dots (CDs), pectin, and acrylic acid triggered construction of the hydrogel network by cross-linker. The antibacterial high-cationic CDs (+51.20 mV) were synthesized by a simple hydrothermal method and released from hydrogel in response to broken hydrogen bonds due to a change in the ambient environment caused by the growing bacteria. The hydrogel showed long-term potent broad-spectrum antibacterial ability (even drug-resistant bacteria) due to the bacterial membrane seriously damaged by the released CDs. The inhibitory capability of this hydrogel was 108.5-fold higher than the other hydrogel. After implantation or incubation with cells, no obvious cytotoxicity or tissue toxicity was observed for the antibacterial hydrogel. This hydrogel enhanced both the application of CDs in vivo and the biosafety of hydrogel. Furthermore, the multicolor fluorescence emission produced by CD provides a potential idea for the development of dual-function hydrogels with in situ monitoring and prevention of bacterial infections to treat wounds.