Chitosan-based composite film dressings with efficient self-diagnosis and synergistically inflammation resolution for accelerating diabetic wound healing

Diabetic wounds with delayed healing are highly susceptible to microbial infection and this seriously affects the life quality of patients. Thus, the development of novel wound dressings featured with rapid diagnosis, effective bacteria eradication, and satisfying biocompatibility is highly desirable to alleviate this issue yet remains critically challenging. In this work, we designed a multi-component composite film by integrating pH-sensitive purple cabbage anthocyanins (PCA), photothermal agent copper sulfide (CuS) nanoparticles, and broad-spectrum antibiotic gentamicin (Gent) into chitosan (CS) film, described as CS/CuS/Gent/PCA film. The composite film dressings are highly sensitive to the pH environment, which could effectively aid the patient to assess the level of infection. Moreover, in vitro experiments showed that the synergistic contributions from the mild photothermal ability under NIR irradiation to CuS and the photothermal-promoted release of Gent could result in an effective bactericidal effect, with a 95.73 % antibacterial ratio. In vivo test further verified that the film dressing with high biosafety could promote the recovery of infected defective skin of diabetic rats, which could heal approximately 92.05 % of open wounds over a two-week course of treatment. Our work provided a promising strategy for the design of advanced wound dressings with smart sensing and anti-information therapy.