Long Wavelength Fluorescein Analogues

Long Wavelength Fluorescein Analogues

Author: Xiaoqing Xiong

Biological imaging in the red and near-infrared (NIR) region is favorable due to its deep tissue penetration and minimal background auto-fluorescence caused by the biomolecules present in living systems. Unfortunately, to date only a limited number of photostable NIR small-molecule fluorophores have been described.

Xiaojun Peng and colleagues, State Key Laboratory of Fine Chemicals, Dalian University of Technology, China, have developed a series of photostable fluorescein analogues (pictured) with absorption and emission in the red or near-infrared region. The synthetic route exploits a Vilsmeier reaction and Knoevenagel condensation.

The new compounds exhibit good photo-physical characteristics. Potential modification of the hydroxyl group provides a method by which the fluorescent properties can be tuned. Three of the analogues specifically localize in mitochondria and one can be utilized to detect Cysteine (Cys) with a turn-on fluorescence in vitro and in vivo.

Based on these results, these new analogues will surely find further applications in the future.


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