Advances in NIR-II Fluorescence Imaging Probes

Abstract

Fluorescence imaging in the second near-infrared window (NIR-II, 1,000-1,700 nm) demonstrates unique advantages of high sensitivity, high temporal and spatial resolution, and excellent image quality in comparison to that in the first near-infrared window (NIR-I, 650-950 nm) due to low scattering of photons and zero background fluorescence in the NIR-II region. Currently, a variety of NIR-II fluorescence imaging probes, such as single-wall carbon nanotubes, quantum dots, rare-earth-doped nanoparticles, conjugated polymer nanoparticles, small molecules, and AIEgens, have been developed as significant imaging tools for basic and clinical research. In this report, we begin with briefly introducing the advances of NIR-II fluorescence molecular probes in the last 10 years, including the design, preparation, and NIR-II fluorescence molecular imaging applications of AIEgens and indocyanine green (ICG). Subsequently, we highlight the large-scale preparation of NIR-II imaging probes and their applications in large animals, including New Zealand white rabbits and cynomolgus monkeys. Finally, we prospect the opportunities and challenges of NIR-II fluorescent molecular imaging probes in basic and translational studies.