A general fluorescence off/on strategy for fluorogenic probes: Steric repulsion-induced twisted intramolecular charge transfer (sr-TICT)

Sci Adv. 2024 Feb 16;10(7):eadi8847. doi: 10.1126/sciadv.adi8847. Epub 2024 Feb 16.

Abstract

Various control strategies are available for building fluorogenic probes to visualize biological events in terms of a fluorescence change. Here, we performed the time-dependent density functional theory (TD-DFT) computational analysis of the twisted intramolecular charge transfer (TICT) process in rhodamine dyes. On the basis of the results, we designed and synthesized a series of rhodamine dyes and established a fluorescence quenching strategy that we call steric repulsion-induced TICT (sr-TICT), in which the fluorescence quenching process is greatly accelerated by simple intramolecular twisting. As proof of concept of this design strategy, we used it to develop a fluorogenic probe, 2-Me PeER (pentyloxyethylrhodamine), for the N-dealkylation activity of CYP3A4. We applied 2-Me PeER for CYP3A4 activity-based fluorescence-activated cell sorting (FACS), providing access to homogeneous, highly functional human-induced pluripotent stem cell (hiPSC)-derived hepatocytes and intestinal epithelial cells. Our results suggest that sr-TICT represents a general fluorescence control method for fluorogenic probes.

MeSH terms

  • Coloring Agents*
  • Cytochrome P-450 CYP3A*
  • Fluorescence
  • Humans
  • Mercaptoethanol
  • Rhodamines

Substances

  • Cytochrome P-450 CYP3A
  • Mercaptoethanol
  • Coloring Agents
  • Rhodamines