A facile injectable carbon dot/oxidative polysaccharide hydrogel with potent self-healing and high antibacterial activity.

Bacterial infection is one of the most formidable problems in wound healing, which inflicts severe pain on patients while causing wound ulceration. Here, we prepared an injectable self-healing carbon dot hydrogel with outstanding antibacterial activity only using ε-poly(L-lysine) carbon dot (PL-CD) and oxidized dextran (ODA). The particle size of PL-CD prepared by pyrolysis of poly-l-lysine was about 3 nm. Moreover, PL-CD with abundant -NH on its surface could not only act as nodes to connect ODA through Schiff base to construct PL-CD@ODA hydrogel network, but also offer excellent antibacterial properties. As the contacting and releasing antibacterial action of the PL-CD@ODA hydrogel, nearly 100 % of the 10 CFU/mL of S. aureus was killed after 10 min of contacting. In addition, PL-CD@ODA hydrogel showed flexible injectability and extremely strong self-healing properties after being severely damaged. When 1000 % shear stress applied to the hydrogel, complete healing could be achieved within a few seconds.