Dynamically crosslinked hydrogel dressings with pH-responsive drug release and antibacterial properties for infected wound healing.

Bacterial infection perturbs the wound microenvironment, thereby profoundly impeding the healing process. Functional hydrogels exhibit unique advantages for treating infected wounds because they possess high drug-loading capacity and well-controlled release performance. Herein, we constructed a dynamic covalent network using carboxymethyl chitosan (CMCS), luteolin (Lut), and 2-formylphenylboronic acid (2-FPBA), fabricating a CFL hydrogel for infected wound healing. Notably, the fabrication of this hydrogel is straightforward, requiring only a simple mixing step without the need for complex chemical modification or purification. This network incorporates Schiff base and boronate ester bonds, endowing it with responsiveness to the acidic microenvironment in infected wounds. Upon exposure to acidic conditions, these bonds dissociate, releasing CMCS and Lut. The released agents work synergistically to combat bacteria and promote wound closure. In addition, the CFL hydrogel exhibits tissue-adhesive properties, antioxidant activity, and good biosafety. In infected full‑thickness skin wounds of rats, the CFL hydrogel led to 99% wound closure by day 11, while also promoting collagen deposition and hair follicle regeneration in the treated wounds. In summary, the developed multifunctional CFL hydrogel represents a viable approach to treating infected skin wounds.