NIR-II emissive properties of 808 nm-excited lanthanide-doped nanoparticles for multiplexed in vivo imaging

The second near-infrared window (1000–1700 nm, NIR-II) emissive lanthanide-doped nanoparticles excited by 808 nm laser are ideal for in vivo bioimaging due to their non-heating excitation. The study of 808 nm excited lanthanide-doped nanoparticles not only provides high-quality NIR-II imaging but also can promote in vivo multiplexed bioimaging under single excitation. Herein, we prepared three sets of typical 808 nm excited lanthanide-doped nanoparticles (NaYF4: Nd3+@NaYF4, NaErF4@NaYF4, and NaYbF4: Er3+/Ce3+@NaYbF4@NaYF4: Yb3+/Nd3+) and then systematically compared their optical properties in the NIR-II window. Furthermore, we prepared water-soluble and biocompatible nanoprobes and achieved multiplexed NIR-II in vivo imaging in mice under single 808 nm excitation. These results highlight the potential of 808 nm excited lanthanide probes for physiological studies and biomedical applications.