Design of NIR-II high performance organic small molecule fluorescent probes and summary of their biomedical applications

Near-infrared fluorescence imaging has gained a lot of attention in biomedicine by virtue of its high sensitivity, high specificity, and many other advantages. Moreover, near-infrared II (NIR-II) fluorescence imaging can further enhance the imaging effect by greatly reducing the absorption, scattering, and autofluorescence of biological tissues, which has pushed the research on fluorescence imaging to a climax. So far, through the unremitting efforts of scholars, the development of NIR-II fluorescent probe has made remarkable progress, especially as the most advantageous organic small molecule fluorophore among fluorescent probes. It has become the main research direction of many scholars. In this review, I summarize the latest progress of organic small molecule fluorescent probes that can be used for NIR-II imaging, including the structure of fluorescent molecules, methods to improve the performance of fluorescent molecules, the delivery of fluorescent probes in organisms, and their applications in biological imaging and tumor therapy.