High-resolution in vivo Imaging, Diagnosis and Treatment Applications of Rare-earth-based Nanomaterials

Fluorescence imaging with the advantages of high spatiotemporal resolution, fast feedback, non-invasiveness, and no ionizing radiation is an important bioimaging technology. Compared with the traditionally used visible and first near-infrared(NIR-I, 650-950 nm) windows, the second near-infrared(NIR-II, 1000-1700 nm) window has lower scattering coefficients and biological autofluorescence, thus effectively improving the resolution, signal-to-noise ratio and penetration depth of bioimaging. Rare-earth-based nanoparticles(RENPs) possess large Stokes shift, high chemical stability, tunable fluorescence lifetimes, and narrow emission bands, making them important fluorescent imaging probes. In recent years, a series of RENPs with excellent NIR-II fluorescence properties have been developed and applied to high-resolution in vivo fluorescence imaging, disease diagnosis and therapy. Herein, the recent research progress of RENPs in high-resolution in vivo fluorescence imaging and theranostics is comprehensively reviewed. Strategies for NIR-? emission enhancement of RENPs, such as dopant regulation, matrix lattice selection, and composite sensitization, are summarized. And their functions of targeting accumulation, fluorescence sensing, disease diagnosis and treatment in multiple biomedical scenes are also introduced. Moreover, their applications in multiplexed imaging, multimodal imaging, and disease diagnosis and treatment are highlighted. Finally, a brief perspective for the future development and challenges of RENPs in biomedical applications is presented.