A Redox-Activatable Fluorescent Sensor for the High-Throughput Quantification of Cytosolic Delivery of Macromolecules

Zhaohui Wang, Min Luo, Chengqiong Mao, Qi Wei, Tian Zhao, Yang Li, Gang Huang, Jinming Gao

Research output: Contribution to journalArticlepeer-review

22 Scopus citations


Efficient delivery of biomacromolecules (e.g., proteins, nucleic acids) into cell cytosol remains a critical challenge for the development of macromolecular therapeutics or diagnostics. To date, most common approaches to assess cytosolic delivery rely on fluorescent labeling of macromolecules with an “always on” reporter and subcellular imaging of endolysosomal escape by confocal microscopy. This strategy is limited by poor signal-to-noise ratio and only offers low throughput, qualitative information. Herein we describe a quantitative redox-activatable sensor (qRAS) for the real-time monitoring of cytosolic delivery of macromolecules. qRAS-labeled macromolecules are silent (off) inside the intact endocytic organelles, but can be turned on by redox activation after endolysosomal disruption and delivery into the cytosol, thereby greatly improving the detection accuracy. In addition to confocal microscopy, this quantitative sensing technology allowed for a high-throughput screening of a panel of polymer carriers toward efficient cytosolic delivery of model proteins on a plate reader. The simple and versatile qRAS design offers a useful tool for the investigation of new strategies for endolysosomal escape of biomacromolecules to facilitate the development of macromolecular therapeutics for a variety of disease indications.

Original languageEnglish (US)
Pages (from-to)1319-1323
Number of pages5
JournalAngewandte Chemie - International Edition
Issue number5
StatePublished - Jan 24 2017


  • FRET
  • activatable sensors
  • drug delivery
  • endolysosomal disruption
  • high-throughput screening

ASJC Scopus subject areas

  • Catalysis
  • Chemistry(all)


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