Dye-Sensitized Rare Earth-Doped Nanoparticles with Boosted NIR-IIb Emission for Dynamic Imaging of Vascular Network-Related Disorders.

Real-time dynamic vascular network imaging can provide accurate hemodynamic and anatomical information, facilitating the diagnosis of blood circulatory system-related diseases and achieving precise evaluation of therapeutic effects. In vivo luminescence imaging in the NIR-IIb biological window (1500-1700 nm) has developed into a next generation of optical imaging method with significantly improved temporal-spatial resolution and penetration depth. Unfortunately, an imaging contrast agent capable of emitting NIR-IIb luminescence with sufficient brightness in this region is lacking. Herein, we designed and proposed a type of dye-sensitized rare earth-doped nanoparticle (RENPs@Alk-pi) with obviously boosted NIR-IIb emission and high biocompatibility, which can be used to realize the real-time NIR-IIb luminescence imaging with high temporal-spatial resolution and contrast. The dye sensitization process provides a 40-fold enhanced brightness of the NIR-IIb emission at 1525 nm of Er3+. Consequently, the RENPs@Alk-pi was not only able to depict a vascular network but also applicable in noninvasively monitoring the dynamic vascular processes and changes in the vascular anatomy of two blood circulatory system-related disorders, including hindlimbs ischemia and atherosclerosis. Our research provides a powerful tool for evaluating vascular network-related dysfunction and physiological processes.