Theranostics 2022; 12(7):3345-3371. doi:10.7150/thno.71359 This issue


Activatable NIR-II organic fluorescent probes for bioimaging

Xiaoning Zhang1*, Shasha Li1*, Huizhen Ma2, Hao Wang1✉, Ruiping Zhang3✉, Xiao-Dong Zhang1,2✉

1. Tianjin Key Laboratory of Brain Science and Neural Engineering, Academy of Medical Engineering and Translational Medicine, Tianjin University, Tianjin 300072, China.
2. Department of Physics and Tianjin Key Laboratory of Low Dimensional Materials Physics and Preparing Technology, School of Sciences, Tianjin University, Tianjin 300350, China.
3. The Third Hospital of Shanxi Medical University, Shanxi Bethune Hospital, Taiyuan, 030000, China.
*Equal contributions to this work.

This is an open access article distributed under the terms of the Creative Commons Attribution License ( See for full terms and conditions.
Zhang X, Li S, Ma H, Wang H, Zhang R, Zhang XD. Activatable NIR-II organic fluorescent probes for bioimaging. Theranostics 2022; 12(7):3345-3371. doi:10.7150/thno.71359. Available from

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Graphic abstract

NIR-II imaging is developed rapidly for noninvasive deep tissue inspection with high spatio-temporal resolution, taking advantage of diminished autofluorescence and light attenuation. Activatable NIR‐II fluorescence probes are widely developed to report pathological changes with accurate targeting, among which organic fluorescent probes achieve significant progress. Furthermore, the activatable NIR‐II fluorescent probes exhibited appealing characteristics like tunable physicochemical and optical properties, easy processability, and excellent biocompatibility. In the present review, we highlight the advances of activatable NIR-II fluorescence probes in design, synthesis and applications for imaging pathological changes like reactive oxygen species (ROS), reactive nitrogen species (RNS), reactive sulfur species (RSS), pH, hypoxia, viscosity as well as abnormally expressed enzymes. This non-invasive optical imaging modality shows a promising prospect in targeting the pathological site and is envisioned for potential clinical translation.

Keywords: NIR-II fluorescence, organic fluorescent probes, responsive probes, pathological changes, bioimaging