Flipping the Switch: Reverse-Demand Voltage-Sensitive Fluorophores

Fluorescence microscopy with fluorescent reporters that respond to environmental cues is a powerful method for interrogating biochemistry and biophysics in living systems. Photoinduced electron transfer (PeT) is commonly used as a trigger to modulate fluorescence in response to changes in the biolog...

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Bibliographic Details
Published in:Journal of the American Chemical Society 2022-07, Vol.144 (29), p.13050-13054
Main Authors: McCann, Jack T., Benlian, Brittany R., Yaeger-Weiss, Susanna K., Knudson, Isaac J., He, Minyi, Miller, Evan W.
Format: Article
Language:English
Subjects:
Electron Transport
Fluorescent Dyes - chemistry
Ionophores
Membrane Potentials
Microscopy, Fluorescence
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Summary:Fluorescence microscopy with fluorescent reporters that respond to environmental cues is a powerful method for interrogating biochemistry and biophysics in living systems. Photoinduced electron transfer (PeT) is commonly used as a trigger to modulate fluorescence in response to changes in the biological environment. PeT-based indicators rely on PeT either into the excited state (acceptor PeT) or out of the excited state (donor PeT). Our group has been developing voltage-sensitive fluorophores (VF dyes) that respond to changes in biological membrane potential (V m). We hypothesize that the mechanism of voltage sensitivity arises from acceptor PeT (a-PeT) from an electron-rich aniline-containing molecular wire into the excited-state fluorophore, resulting in decreased fluorescence at negative V m. In this work, we reversed the direction of electron flow to access donor-excited PeT (d-PeT) VF dyes by introducing electron-withdrawing rather than electron-rich molecular wires. VF dyes containing electron-withdrawing groups show voltage-sensitive fluorescence, but with the opposite polarity: hyperpolarizing V m now gives fluorescence increases. We used a combination of computation and experiment to design and synthesize five d-PeT VF targets, two of which are voltage-sensitive.
ISSN:0002-7863
1520-5126
DOI:10.1021/jacs.2c05385