近红外二区有机小分子荧光探针

Fluorescence imaging plays an important role in the diagnosis and treatment of major diseases by virtue of its high sensitivity, strong specificity and excellent spatio-temporal resolution. However, traditional near-infrared-I (NIR-I, 700~900 nm) fluorescence imaging often encounters multiple concerns such as poor tissue penetration, which limits its clinical application. In recent years, near-infrared-II (NIR-II, 1000~1700 nm) fluorescence imaging has been proven to provide better imaging qualities, higher signal-to-noise ratio and deeper tissue penetration than those observed in the NIR-I window due to the diminished photon scattering and tissue auto-fluorescence. Among NIR-II fluorescent probes, organic small molecules are becoming research hotspots in this field due to their advantages of low toxicity, simple structure and fast metabolism. This review describes the recent progress in the design of organic small molecule NIR-II probes and the strategies for improving the fluorescence quantum yield. The application of small molecule NIR-II probes in activatable imaging, multimode imaging and theranostics are evaluated systematically. Current challenges and future perspectives in this emerging field are also prospected.