Boosted Energy Migration System in NIR-IIc Rare-Earth Nanoprobe for Deep-Tissue Multiplexed Bioimaging

Rare-earth nanoparticles represent a promising class of NIR-IIc emitters for deep-tissue bioimaging beyond 1700 nm; however, the practical application remains limited by their suboptimal luminescence brightness and the low quantum efficiency (QE) of current detectors. Here we report a dual-sensitizer rare-earth nanoprobe (YbEr:Tm) that strategically steers Er-Er energy migration into the favorable ⁴I_13/2 → ⁴I_13/2 channel, yielding a 43.5-fold enhancement of Tm³⁺ emission in the NIR-IIc window. The resulting YbEr:Tm nanoprobes afford 180 µm spatial resolution through 1.5 cm of thoracic muscle, even under the constraints of a low-QE extended-range InGaAs detector. Building on this brightness, we achieve the first dynamic multiplexed NIR-IIc in vivo bioimaging by exploiting the lifetime disparity between rare-earth nanoprobes and PbS quantum dots. Furthermore, an implantable three-plex NIR-IIc optical cipher is devised, in which distinct nanoprobes with orthogonal lifetimes and spectral profiles enable information encryption within subcutaneous tissue and real-time, noninvasive retrieval.