A high-contrast NIR excitation probe for monitoring Cu²⁺ in the endoplasmic reticulum for synergistic cuproptosis and ferroptosis anticancer therapy

Currently, the study of cuproptosis focuses on the Cu²⁺-induced morphology changes in mitochondria (Mito), and the observation of the effect of endoplasmic reticulum (ER)-related Cu²⁺ content on cuproptosis is relatively lacking. Herein, we have developed a hydroxyflavone (HF)-based NIR excited two-photon fluorescent probe, BHCO, that exhibits specific recognition of Cu²⁺ with high resolution. BHCO-Cu²⁺ (Cu2BC) can lead to DLAT protein aggregation, triggering cuproptosis. Furthermore, Cu2BC can upregulate reactive oxygen species (ROS) under 720 nm excitation, which facilitates ferroptosis. The synergistic effect of ferroptosis and cuproptosis leads to the damage of cellular mitochondria and endoplasmic reticulum, resulting in the severe death of cancer cells. We are firmly convinced that our nonlinear optical (NLO) small molecule probe for monitoring Cu²⁺ could provide a valid tool for rapid tumor elimination through synergistic ferroptosis and cuproptosis.