A dual lock-and-key probe for high-fidelity visualizing abdominal aortic aneurysm-related inflammation via a PET-TICT integrated near-infrared platform

The evaluation of the inflammatory response in the abdominal aortic aneurysm (AAA) is a great challenge. Optical imaging probes enable us to detect and reveal the physiological and pathological functions of analytes of interest in a non-invasive and longitudinal manner at the molecular level. However, optical imaging probes usually use a single action mechanism, which is easy to produce false positive or false negative phenomenon, resulting inadequate accuracy and sensitivity. On the contrary, fluorescent probes with two interaction sensing mechanisms provide different fluorescence signals or amplify response signals, which is beneficial to track multiple analytes meantime or improve the selectivity and sensitivity of chemical sensors. In this work, a dual-sensing fluorescent probe (Vis-HClO) was successfully constructed by combining photoinduced electron transfer with torsional charge transfer (PET-TICT). The results show that only in the environment of high viscosity and the presence of hypochlorite (HClO), the PET and TICT of Vis-HClO are broken at the same time, thus releasing obvious red fluorescence. In addition, using QCy7 as a fluorescent group, not only gives the probe a large Stokes shift, reduces the crosstalk and self-absorption of excitation and emission spectra, but also its positively charged indole quaternary ammonium heterocycle can be used as a mitochondrial targeting group to improve the sensitivity of HClO detection. In the process of inflammation, the intracellular viscosity level and HClO content increase at the same time, while the viscosity changes are not obvious in other physiological or pathological processes such as oxidative stress, so as to ensure the accurate imaging analysis of the cellular inflammatory process.