COX-2-targeted fluorescent probe for ClO^- monitoring in precise cancer detection

Hypochlorite anion (ClO^-) is closely associated with cancer development and progression, necessitating precise monitoring of ClO^- in tumor sites, and Cyclooxygenase-2 (COX-2 is highly expressed in tumor cells. So we rationally designed two ClO^--specific responsive fluorescent probes COX2-ClO1 and COX2-ClO2, using indomethacin (IMC) as the COX-2 targeting moiety and methylene blue as fluorophore unit. Both probes exhibited high selectivity and sensitivity towards ClO^- in the in vitro solution assays and possess excellent biocompatibility in cellular experiments. Compared to COX2-ClO1, COX2-ClO2 exhibited superior targeting specificity for COX-2, enabling precise differentiation between tumor cells and normal cells and allowing imaging of both exogenous and endogenous ClO^- in the in vivo experiments. Moreover, COX2-ClO2 could accurately target the tumor site in xenograft mice and is likely metabolized by the kidneys.