A LRET Nanoplatform Consisting of Lanthanide and Amorphous Manganese Oxide for NIR‐II Luminescence Lifetime Imaging of Tumor Redox Status

Abstract

Designing luminescence lifetime sensors in the second near-infrared (NIR-II) window is a great challenge due to the difficult structural construction. Here, we report a tumor redox responsive and easily synthesized material, amorphous manganese oxide (MnO_x ) with indirect band gap of 1.02 eV, as an energy acceptor to build a luminescence resonance energy transfer (LRET) toolbox for universally regulating NIR-I to NIR-II luminescence lifetimes of lanthanide nanoparticles, in which energy transfer is based on matched energy gap instead of conventional overlapped spectra. We further utilize ytterbium (Yb³⁺ )-doped YbNP@MnO_x as an NIR-II luminescence lifetime sensor to realize in vitro quantitative redox visualization with relative errors under 5 % in samples covered with mouse skin. Furthermore, HepG2 cells and tumors with high redox state have been accurately distinguished by NIR-II luminescence lifetime imaging. The quantified intracellular and intratumor glutathione (GSH) levels are highly consistent with the commercial kit results, illustrating the reliable redox visualization ability in biological tissue.