Fluorescence activation imaging of cytochrome c released from mitochondria using aptameric nanosensor

J Am Chem Soc. 2015 Jan 21;137(2):982-9. doi: 10.1021/ja511988w. Epub 2015 Jan 12.


We have developed an aptameric nanosensor for fluorescence activation imaging of cytochrome c (Cyt c). Fluorescence imaging tools that enable visualization of key molecular players in apoptotic signaling are essential for cell biology and clinical theranostics. Cyt c is a major mediator in cell apoptosis. However, fluorescence imaging tools allowing direct visualization of Cyt c translocation in living cells have currently not been realized. We report for the first time the realization of a nanosensor tool that enables direct fluorescence activation imaging of Cyt c released from mitochondria in cell apoptosis. This strategy relies on spatially selective cytosolic delivery of a nanosensor constructed by assembly of a fluorophore-tagged DNA aptamer on PEGylated graphene nanosheets. The cytosolic release of Cyt c is able to dissociate the aptamer from graphene and trigger an activated fluorescence signal. The nanosensor is shown to exhibit high sensitivity and selectivity, rapid response, large signal-to-background ratio for in vitro, and intracellular detection of Cyt c. It also enables real-time visualization of the Cyt c release kinetics and direct identification of the regulators for apoptosis. The developed nanosensor may provide a very valuable tool for apoptotic studies and catalyze the fundamental interrogations of Cyt c-mediated biology.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Apoptosis
  • Aptamers, Nucleotide / chemistry*
  • Aptamers, Nucleotide / metabolism*
  • Biosensing Techniques / methods*
  • Cell Survival
  • Cytochromes c / metabolism*
  • Graphite / chemistry
  • HeLa Cells
  • Humans
  • MCF-7 Cells
  • Mitochondria / metabolism*
  • Models, Molecular
  • Nanostructures / chemistry
  • Nanotechnology / instrumentation*
  • Nucleic Acid Conformation
  • Optical Imaging*
  • Oxides / chemistry
  • Protein Conformation


  • Aptamers, Nucleotide
  • Oxides
  • Graphite
  • Cytochromes c