An AIE-based fluorescence probe for assessing treatment response of bacteria-infected wound

The integration of precise bacterial detection with effective sterilization, while mitigating the risk of bacterial resistance, is of paramount importance in clinical medicine and public health. Herein, we present a novel aggregation-induced emission (AIE) fluorescent probe, PTZ-PD, engineered for the simultaneous detection and eradication of bacteria in animal models. PTZ-PD features a donor-acceptor (D-A) architecture composed of a phenothiazine donor and a quinoline propionitrile acceptor, which endows the probe with long-wavelength emission (λ_em ≈ 680 nm) and remarkable AIE characteristics, enabling quantitative detection of bacteria. The probe exhibited high sensitivity, achieving detection limits (LOD) of 1.01 × 10³ CFU/mL for Staphylococcus aureus (S. aureus) and 2.28 × 10³ CFU/mL for Escherichia coli (E. coli) within 1 min. Furthermore, PTZ-PD demonstrated potent light-activated antibacterial activity, achieving inhibition rates of 98.3% against S. aureus and 92.7% against E. coli after only 30 min of sunlight irradiation. Mechanistic studies using reactive oxygen species (ROS)-sensitive fluorescent probes revealed that the bactericidal effect is mediated by light-induced ROS generation. The fluorescence of the probe was also responsive to environmental viscosity. Importantly, in a murine wound infection model, PTZ-PD effectively promoted healing and demonstrated excellent biosafety. This work not only enriches the toolbox of AIE-based theragnostic agents but also provides a promising candidate for combating bacterial infections and informing future drug development.