A tunable fluorescent probe for superoxide anion detection during inflammation caused by Treponema pallidum

Syphilis, caused by Treponema pallidum (T. pallidum), is associated with the oxidative stress due to its inflammation-like symptom, and detecting the reactive oxygen species (ROS) is crucial for monitoring the infectious process. Herein, we design and synthesize a perylene-based tunable fluorescent probe, PerqdOH, which can detect endogenous O-2(center dot) during T. pallidum infection. The fluorescence peak shifted from 540 nm to 750 nm with increasing O-2(center dot-) levels. Besides, both decreased green fluorescence and enhanced red fluorescence could be observed simultaneously during the in vitro infection, providing the real-time monitoring of intracellular O-2(center dot-) caused by T. pallidum. Furthermore, the probe exhibited a remarkable signal in the treponemal lesions on the back of a rabbit model. Taken together, our synthesized PerqdOH holds great potential for application in clarifying the infectious process caused by T. pallidum in real time.

Automated summary

We designed and synthesized a new fluorescent probe, PerqdOH, which can monitor intracellular O-2(center dot-) during T. pallidum infection in real time. In vitro infection experiments showed decreased green fluorescence and enhanced red fluorescence simultaneously. The probe also exhibited a remarkable signal in treponemal lesions in a rabbit model. PerqdOH has great potential for application in clarifying the infectious process caused by T. pallidum in real time.