Cuproptosis accompanied by obvious •OH generation revealed with an ultrasensitive NIR fluorescence probe

Cuproptosis is a recently discovered copper-dependent pathway of regulated cell death, and may play a role in a number of physiological and pathological processes; however, the variation of reactive oxygen species such as OH level is unclear during cuproptosis. Herein, we have developed an ultrasensitive near-infrared (NIR) fluorescence probe CDHQ for characterizing cuproptosis, which reveals an obvious hydroxyl radical (OH) generation during cuproptosis. The specific hydrogen abstraction of OH causes a large π-conjugation extension and spectral shift of CDHQ, accompanied by a high-contrast fluorescence off–on response. CDHQ can detect trace OH that is undetectable by other methods such as electron spin resonance during autoxidation of low-valent metals (Fe2+, Ti3+, V3+ and especially Cu+) in the absence of H2O2. Using CDHQ, we have found that OH is significantly generated in the copper-overloaded cells of cuproptosis, even before cell death. Moreover, CDHQ is capable of monitoring the generation of OH in living mice, and thus may be expected to be useful for studying the in vivo change of OH in more biosystems.