Single-molecule sensing of caspase activation in live cells via plasmon coupling nanotechnology

Methods Enzymol. 2014;544:271-97. doi: 10.1016/B978-0-12-417158-9.00011-X.


Apoptotic caspases execute programmed cell death, where low levels of caspase activity are linked to cancer (Kasibhatla & Tseng, 2003). Chemotherapies utilize induction of apoptosis as a key mechanism for cancer treatment, where caspase-3 is a major player involved in dismantling these aberrant cells. The ability to sensitively measure the initial caspase-3 cleavage events during apoptosis is important for understanding the initiation of this complex cellular process; however, current ensemble methods are not sensitive enough to measure single cleavage events in cells. To overcome this, we describe a procedure to develop peptide-linked gold nanoparticles that have unique optical properties and can serve as beacons to visualize the apoptotic drug response in cancer cells at the single-molecule level. By thorough analyses of their trajectories, one can reveal early-stage caspase-3 activation in live cells continuously and with no ambiguity.

Keywords: Caspase; Gold nanoparticles; Live cells; Plasmon coupling; Single molecule.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acid Sequence
  • Animals
  • Apoptosis
  • Biosensing Techniques / instrumentation*
  • Caspase 3 / metabolism*
  • Cell Survival
  • Colonic Neoplasms / enzymology
  • Enzyme Activation*
  • Enzyme Assays / instrumentation
  • Equipment Design
  • Gold / chemistry
  • Gold / metabolism*
  • Humans
  • Microscopy / instrumentation
  • Molecular Sequence Data
  • Nanoparticles / chemistry
  • Nanoparticles / metabolism*
  • Nanoparticles / ultrastructure
  • Nanotechnology / instrumentation*
  • Peptides / chemistry
  • Peptides / metabolism*


  • Peptides
  • Gold
  • Caspase 3