An expanded palette of fluorogenic HaloTag probes with enhanced contrast for targeted cellular imaging

08 February 2022, Version 2
This content is a preprint and has not undergone peer review at the time of posting.


We report the development of HaloTag fluorogens based on dipolar flexible molecular rotor structures. By modulating the electron donating and withdrawing groups, we have tuned the absorption and emission wavelengths to design a palette of fluorogens with emissions spanning the green to red range. The probes were studied in glycerol and in presence of HaloTag and exhibited good fluorogenic properties thanks to a viscosity-sensitive emission. In live-cell confocal imaging, the fluorogens yielded only a very low non-specific signal that enabled wash-free targeted imaging of intracellular organelles and proteins with good contrast.


Fluorogenic probes
Fluorescence imaging
molecular rotors

Supplementary materials

Supplementary Information
materials and methods, synthetic and molecular biology procedures, additional figures and schemes


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