Auxochrome Dimethyl-Dihydroacridine Improves Fluorophores for Prolonged Live-Cell Super-Resolution Imaging

J Am Chem Soc. 2024 Mar 13;146(10):6566-6579. doi: 10.1021/jacs.3c11823. Epub 2024 Feb 29.

Abstract

Superior photostability, minimal phototoxicity, red-shifted absorption/emission wavelengths, high brightness, and an enlarged Stokes shift are essential characteristics of top-tier organic fluorophores, particularly for long-lasting super-resolution imaging in live cells (e.g., via stimulated emission depletion (STED) nanoscopy). However, few existing fluorophores possess all of these properties. In this study, we demonstrate a general approach for simultaneously enhancing these parameters through the introduction of 9,9-dimethyl-9,10-dihydroacridine (DMA) as an electron-donating auxochrome. DMA not only induces red shifts in emission wavelengths but also suppresses photooxidative reactions and prevents the formation of triplet states in DMA-based fluorophores, greatly improving photostability and remarkably minimizing phototoxicity. Moreover, the DMA group enhances the fluorophores' brightness and enlarges the Stokes shift. Importantly, the "universal" benefits of attaching the DMA auxochrome have been exemplified in various fluorophores including rhodamines, difluoride-boron complexes, and coumarin derivatives. The resulting fluorophores successfully enabled the STED imaging of organelles and HaloTag-labeled membrane proteins.

MeSH terms

  • Fluorescent Dyes*
  • HeLa Cells
  • Humans
  • Ionophores
  • Microscopy, Fluorescence / methods
  • Rhodamines

Substances

  • Fluorescent Dyes
  • Rhodamines
  • Ionophores