Imaging of Colorectal Cancers Using Activatable Nanoprobes with Second Near-Infrared Window Emission.

Fluorescent probes in the second near-infrared window (NIR-II) allow high-resolution bioimaging with deep-tissue penetration. However, existing NIR-II materials often have poor signal-to-background ratios because of the lack of target specificity. Herein, an activatable NIR-II nanoprobe for visualizing colorectal cancers was devised. This designed probe displays H2 S-activated ratiometric fluorescence and light-up NIR-II emission at 900-1300 nm. By using this activatable and target specific probe for deep-tissue imaging of H2 S-rich colon cancer cells, accurate identification of colorectal tumors in animal models were performed. It is anticipated that the development of activatable NIR-II probes will find widespread applications in biological and clinical systems.