In Vivo High-Contrast Biomedical Imaging in the Second Near-Infrared Window Using Ultrabright Rare-Earth Nanoparticles

Le résumé fourni par la source

Intravital luminescence imaging in the second near-infrared window (NIR-II) enables noninvasive deep-tissue imaging with high spatiotemporal resolution of live mammals because of the properties of suppressed light scattering and diminished autofluorescence in the long-wavelength region. Herein, we present the synthesis of a downconversion luminescence rare-earth nanocrystal with a core–shell–shell structure (NaYF 4 @NaYbF 4:Er,Ce@NaYF 4:Ca). The structure efficiently maximized the doping concentration of the sensitizers and increased Er 3+ luminescence while preventing cross relaxation. Furthermore, Ce 3+ doping in the middle layer efficiently limited the upconversion pathway and increased downconversion by 24-fold to produce bright 1550 nm luminescence under 975 nm excitation. Finally, optimizing the inert shell coating of NaYF 4:Ca and liposome encapsulation reduced the luminescence quenching impact by water and improved biological metabolism. Thus, our synthesized biocompatible, ultrabright NIR-II probes provide high contrast and resolution for through-scalp and through-skull luminescence imaging of mice cerebral vasculature without craniotomy as well as imaging of mouse hindlimb microvessels.

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