pH-triggered visible indicator dressing for early diagnosis of bacterial wound infection

Cutaneous wound infections affect millions of patients annually worldwide, and diagnosing wound infections in the early stage is crucial for guiding timely and appropriate anti-infection treatment. Importantly, bacterial infections alter wound pH, thereby offering a promising approach for early diagnosis of wound infections. Herein, a diagnostic smart dressing (CMC-PDBI) is developed by ultraviolet-initiated crosslinking of a pH-responsive indicator coating, incorporating modified bromothymol blue, onto a carboxymethyl cellulose substrate for preclinical diagnosis of bacterial wound infections. The developed dressing exhibits superior pH-triggered color-changing performance in both phosphate buffer solution and bacterial cultures across the pH range associated with wound infection. In a murine wound infection model, the CMC-PDBI dressing demonstrates the ability to indicate wound infection two days before symptomatic manifestation. Subsequent wound healing evaluation in mice proves that early therapy intervention guided by CMC-PDBI dressing facilitates wound healing and reduces inflammation. Moreover, a smartphone application (In-fectSense) has been created, aiming to assist in identifying the risk of wound infections using CMC-PDBI. This work presents a novel infection early-warning platform with high potential for qualitative visual diagnosis of wound infections before the clinical symptom onset. It may open new vistas in wound management in both clinical and home care.