A Novel Afterglow Molecular Probe for Monitoring of pH and Viscosity in Infected Wounds with Two-Dimensional Signal

Organic afterglow materials have shown tremendous potential in the field of biomedical imaging. However, reports on small-molecule afterglow probes, particularly those with multitarget detection capabilities, remain limited. Here, we report a novel afterglow molecule probe ( Hcy-Br-SO ) that effectively responds to changes in pH and viscosity during wound infection, based on a two-dimensional (2D) signal. In this design, the enhancement of molecular afterglow performance was achieved through molecular engineering, and the underlying mechanism of afterglow emission was derived. Additionally, the synergistic enhancement of the afterglow intensity of Hcy-Br-SO by the increase in the pH and viscosity was confirmed. Besides, we observed that viscosity could retard the photoreaction process, thereby extending the duration of afterglow emission. Based on this phenomenon, we transformed the traditional time-dependent characteristics of afterglow into a measurable parameter for monitoring viscosity changes. It is noteworthy that the introduction of the time dimension not only facilitates the separation of signal sources but also explores the application potential of afterglow molecular probes. To the best of our knowledge, this is the first afterglow small-molecule probe that uses 2D signals (intensity and half-life) to monitor binocular targets. Furthermore, the Hcy-Br-SO probe was successfully used to distinguish between normal and infected wounds. This work may be useful to unravel the pathological mechanisms of chronic wounds and provide guidance for intervention.