Integration of Time‐Gated Luminescence and 19 F Magnetic Resonance in Lanthanide Complexes‐Based Probes for Quantitative Imaging of Mitochondrial Superoxide Anions

ABSTRACT Time‐gated luminescence (TGL) bioimaging offers high‐sensitivity biosensing with background‐free characteristics, yet its limited tissue penetration constrains broad in vivo applications. To address this issue, we developed unique lanthanide complexes to act as modular probes that integrate the high‐sensitivity of TGL and deep‐tissue imaging capability of 19 F magnetic resonance (MR). The probes are constructed from a multifunctional ligand, Mito‐BOTTA, comprising a mitochondria‐targeting 1‐(2‐aminoethyl)‐4‐methylpyridinium group, a superoxide anion (O 2 •− )‐responsive 3,5‐bis(trifluoromethyl)benzenesulfonyl (TFBS) moiety, and a terpyridine polyacid‐derived scaffold for coordination to Eu 3+ , Tb 3+ , or Gd 3+ . The coordination with Eu 3+ /Tb 3+ ‐mixture produces a ratiometric TGL probe Mito‐BOTTA‐Eu 3+ /Tb 3+ that, upon O 2 •− ‐triggered cleavage of the TFBS moiety, exhibits a pronounced increase in Tb 3+ emission at 538 nm, accompanied by a decrease in Eu 3+ emission at 608 nm. This reciprocal spectral response enables precise and autofluorescence‐free ratiometric TGL imaging of mitochondrial O 2 •− using the I 538 / I 608 ratio as a quantitative readout. In parallel, the complexation with Gd 3+ yields Mito‐BOTTA‐Gd 3+ , where the paramagnetic Gd 3+ ion quenches the 19 F MR signal. The cleavage of TFBS in the presence of O 2 •− releases the fluorinated TFBS moiety, which restores the 19 F MR signal, enabling a complementary “turn‐on” MR detection for O 2 •− . Both probes demonstrated excellent mitochondrial localization, low cytotoxicity, and robust responsiveness to O 2 •− in HepG2 cells as well as in murine models of alcohol‐ and CCl 4 ‐induced acute liver injuries, which suggested the potential of the probes for dual‐mode TGL and 19 F MR bioimaging of O 2 •− , offering a promising approach for the diagnostics of oxidative stress‐related diseases.