Peptide-nanoparticle hybrid SERS probes for optical detection of protease activity

J Nanosci Nanotechnol. 2007 Jul;7(7):2323-30. doi: 10.1166/jnn.2007.444.


Real-time in situ detection of active proteases is crucial for early-stage cancer screening and cell signaling pathway study; however, it is difficult to achieve using fluorescence or radioactive probes at volumes below 1 nL. Here we demonstrated a hybrid optical probe by incorporating nanocrescent particle and peptides with artificial tag molecules. We performed a proof-of-concept study using prostate specific antigen (PSA), one of the most prominent prostate cancer markers, and a serine protease present in patients' seminal fluid and serum. The Raman spectral signal from the tag molecules is enhanced by the nanocrescent and the signal is monitored as the indicator for peptide cleavage in a femtoliter reaction volume, at levels close to a single proteolytically active PSA molecule. The high reaction specificity of the peptides on individual nanoparticles minimizes the false detection of other serine proteases and background Raman signal, which results in a high-fidelity and high-signal-to-noise-ratio cancer nanoprobe that can be easily incorporated into nano/microfluidic devices.

Publication types

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

MeSH terms

  • Crystallization / methods
  • Enzyme Activation
  • Humans
  • Macromolecular Substances / chemistry
  • Male
  • Materials Testing
  • Molecular Conformation
  • Molecular Probe Techniques*
  • Nanostructures / chemistry*
  • Nanostructures / ultrastructure
  • Nanotechnology / methods*
  • Optics and Photonics
  • Particle Size
  • Peptide Hydrolases / chemistry*
  • Peptides / chemistry*
  • Prostate-Specific Antigen / analysis*
  • Sensitivity and Specificity
  • Spectrum Analysis, Raman / methods*
  • Surface Properties


  • Macromolecular Substances
  • Peptides
  • Peptide Hydrolases
  • Prostate-Specific Antigen