A reversible peptide-based nanoprobe for visualizing the mechanism of copper-histidine interaction-induced cuproptosis in cancer cells

L -Histidine ( L -His) is a natural ligand for Cu 2+ . The high demand for Cu 2+ in cancer cells and their unique microenvironment favor interactions between Cu 2+ and L -His interactions. However, the specific effects of Cu 2+ – L -His interactions on the fate of cancer cells remain to be elucidated. In this study, we developed a novel, reversible, peptide-based fluorescent nanoprobe, L (fluorescein isothiocyanate–aminocaproic acid–alanine–serine–arginine–His), for visualizing the sequential sensing of exogenous Cu 2+ – L -His interactions in living cells in an “on–off–on” response mode. As a bioprobe with dual colorimetric and fluorescence functions, L can be used for on-site visualization, enabling rapid detection of Cu 2+ and L -His in aqueous solutions. The probe exhibits high sensitivity, with limits of detection as low as 8.8 nM and 11.7 nM for Cu 2+ and L -His, respectively. The successful visualization of the in situ interaction between exogenous Cu 2+ and L -His in cancer cells is attributed to the good fluorescence stability, broad pH applicability, cyclic detection capability, and low toxicity of L . Furthermore, the interaction between exogenous Cu 2+ and L -His was found to specifically induce cuproptosis in cancer cells while causing minimal effects on normal cells. Collectively, our findings demonstrate that the combined administration of Cu 2+ and L -His represents a promising antitumor strategy, particularly for tumors with high Cu 2+ demand.