A Versatile Palette of Fluorescent Probes

Roberti, Julia

January 24, 2022

A Versatile Palette of Fluorescent Probes

For live cell confocal and nanoscopy imaging

Fluorescence confocal and STED imaging have become powerful tools to explore the workings of the living cell, and the development of new probes is fundamental to do this at the right spatial and temporal scales. Permeable fluorogenic probes are very attractive because they can penetrate cells and bind specifically to the target of interest while significantly increasing their fluorescence intensity. This results in higher signal-to-noise ratios and low unspecific background signals. The “chemical trick” fluorogenic probes play is to exist as two states in equilibrium: one hydrophilic and fluorescent zwitterionic “open” form, and one hydrophobic non-fluorescent “closed” form that is cell permeable.

Read the full article:

Wang, L. et al.:

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

Nature Chemistry volume 12, pages 165–172 (2020)

https://www.nature.com/articles/s41557-019-0371-1

Researchers at the Max Planck Institute for Medical Research in Heidelberg have developed a general strategy to synthesize live-cell compatible fluorogenic probes, and the result are the new MaP (Max Planck) probes. By introducing a smart chemical modification, the equilibrium shifts towards the “closed” form and maximizes cell permeability and with minimal background, and it shifts back to the fluorescent “open” form upon binding to the target of interest. The MaP probes are highly fluorogenic, showing an increase in fluorescence up to 1000-fold, and allow straightforward imaging without the need of any washing steps. The design principle, first tested on 6-TAMRA, produced probes with spectral properties spanning the entire spectrum of the visible light and suitable for live-cell imaging of proteins associated with cytoskeleton, mitochondria, and nuclei with confocal as well as STED super-resolution microscopy.

The study, conducted by Lu Wang during his postdoc at the Max Planck Institute’s Department of Chemical Biology, directed by Kai Johnsson, was published in Nature Chemistry.