A general strategy to develop cell permeable and fluorogenic probes for multicolour nanoscopy

  • Nat Chem. 2020 Feb;12(2):165-172. doi: 10.1038/s41557-019-0371-1.
Lu Wang  1 ,  Mai Tran  2 ,  Elisa D'Este  3 ,  Julia Roberti  4 ,  Birgit Koch  2 ,  Lin Xue  2 ,  Kai Johnsson  5  6
Affiliations
  • 1. Department of Chemical Biology, Max Planck Institute for Medical Research, Heidelberg, Germany. [email protected].
  • 2. Department of Chemical Biology, Max Planck Institute for Medical Research, Heidelberg, Germany.
  • 3. Optical Microscopy Facility, Max Planck Institute for Medical Research, Heidelberg, Germany.
  • 4. Leica Microsystems CMS GmbH, Mannheim, Germany.
  • 5. Department of Chemical Biology, Max Planck Institute for Medical Research, Heidelberg, Germany. [email protected].
  • 6. Institute of Chemical Sciences and Engineering, École Polytechnique Fédérale de Lausanne, Lausanne, Switzerland. [email protected].
PMID: 31792385 DOI: 10.1038/s41557-019-0371-1
Abstract

Live-cell fluorescence nanoscopy is a powerful tool to study cellular biology on a molecular scale, yet its use is held back by the paucity of suitable fluorescent probes. Fluorescent probes based on regular fluorophores usually suffer from a low cell permeability and an unspecific background signal. Here we report a general strategy to transform regular fluorophores into fluorogenic probes with an excellent cell permeability and a low unspecific background signal. Conversion of a carboxyl group found in rhodamines and related fluorophores into an electron-deficient amide does not affect the spectroscopic properties of the fluorophore, but allows us to rationally tune the dynamic equilibrium between two different forms: a fluorescent zwitterion and a non-fluorescent, cell-permeable spirolactam. Furthermore, the equilibrium generally shifts towards the fluorescent form when the probe binds to its cellular targets. The resulting increase in fluorescence can be up to 1,000-fold. Using this simple design principle, we created fluorogenic probes in various colours for different cellular targets for wash-free, multicolour, live-cell nanoscopy.

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