Norcyanine-Carbamates Are Versatile Near-Infrared Fluorogenic Probes

J Am Chem Soc. 2021 Apr 21;143(15):5674-5679. doi: 10.1021/jacs.1c02112. Epub 2021 Apr 12.

Abstract

Fluorogenic probes in the near-infrared (NIR) region have the potential to provide stimuli-dependent information in living organisms. Here, we describe a new class of fluorogenic probes based on the heptamethine cyanine scaffold, the most broadly used NIR chromophore. These compounds result from modification of heptamethine norcyanines with stimuli-responsive carbamate linkers. The resulting cyanine carbamates (CyBams) exhibit exceptional turn-ON ratios (∼170×) due to dual requirements for NIR emission: carbamate cleavage through 1,6-elimination and chromophore protonation. Illustrating their utility in complex in vivo settings, a γ-glutamate substituted CyBam was applied to imaging γ-glutamyl transpeptidase (GGT) activity in a metastatic model of ovarian cancer. Overall, CyBams have significant potential to extend the reach of fluorogenic strategies to intact tissue and live animal imaging applications.

Publication types

  • Research Support, N.I.H., Intramural

MeSH terms

  • Animals
  • Carbamates / chemistry*
  • Carbocyanines / chemistry*
  • Cell Line, Tumor
  • Disease Models, Animal
  • Female
  • Fluorescence Resonance Energy Transfer
  • Fluorescent Dyes / chemistry*
  • Humans
  • Mice
  • Microscopy, Confocal
  • Neoplasm Metastasis
  • Ovarian Neoplasms / diagnostic imaging
  • Ovarian Neoplasms / metabolism
  • Spectroscopy, Near-Infrared
  • Transplantation, Heterologous
  • gamma-Glutamyltransferase / chemistry
  • gamma-Glutamyltransferase / metabolism

Substances

  • Carbamates
  • Carbocyanines
  • Fluorescent Dyes
  • gamma-Glutamyltransferase