Tailoring Versatile Nanoheterojunction-Incorporated Hydrogel Dressing for Wound Bacterial Biofilm Infection Theranostics

Wound-infected bacterial biofilms are protected by self-secreted extracellular polymer substances (EPS), which can confer them with formidable resistance to the host's immune responses and antibiotics, and thus delays in diagnosis and treatment can cause stubborn infections and life-threatening complications. However, tailoring an integrated theranostic platform with the capability to promptly diagnose and treat wound biofilm infection still remains a challenge. Herein, a versatile erbium-doped carbon dot-encapsulated zeolitic imidazolate framework-8 (Er:CDs@ZIF-8) nanoheterojunction (C@Z nano-HJ) is tailored and incorporated into gelatin methacrylate/poly(N-hydroxyethyl acrylamide) (GelMA/PHEAA)-based tough and sticky hydrogel dressing (GH-C@Z) to achieve wound biofilm infection-integrated theranostic application. Stimulated by the acidic microenvironment of the biofilm, the turn-on response of the C@Z in the dressing assists the biofilm infection monitoring by exhibiting cyan fluorescence. Meanwhile, C@Z can effectively destroy the EPS barrier and accomplish photothermal-photodynamic-ion interference synergistic antibacterial therapy under near-infrared light. Furthermore, after the effective eradication of biofilm, the potent antioxidant properties of released Er:CDs allow the dressing to attenuate reactive oxygen species and mitigate inflammatory responses, which finally promote collagen deposition and neovascularization to accelerate wound healing. Overall, this tailored wound dressing provides insight into the development of versatile diagnostic and therapeutic platforms for bacterial biofilm infections.