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Abstract
Fluorescent imaging of biological systems in the second near-infrared window (NIR-II) can probe tissue at centimetre depths and achieve micrometre-scale resolution at depths of millimetres. Unfortunately, all current NIR-II uorophores are excreted slowly and are largely retained within the reticuloendothelial system, making clinical translation nearly impossible. Here, we report a rapidly excreted NIR-II uorophore (90% excreted through the kidneys within 24 h) based on a synthetic 970-Da organic molecule (CH1055). The uorophore outperformed indocyanine green (ICG)a clinically approved NIR-I dyein resolving mouse lymphatic vasculature and sentinel lymphatic mapping near a tumour. High levels of uptake of PEGylated-CH1055 dye were observed in brain tumours in mice, suggesting that the dye was detected at a depth of 4 mm. The CH1055
dye also allowed targeted molecular imaging of tumours in vivo when conjugated with anti-EGFR Abody. Moreover, a superior tumour-to-background signal ratio allowed precise image-guided tumour-removal surgery.