Label-free and highly sensitive biomolecular detection using SERS and electrokinetic preconcentration

Lab Chip. 2009 Dec 7;9(23):3360-3. doi: 10.1039/b912076a. Epub 2009 Oct 1.


In this paper, we present a method combining surface-enhanced Raman scattering (SERS) spectroscopy to detect biomolecules in a label-free way with an electrokinetic preconcentration technique (electrophoresis) to amplify biomolecular signals at low concentrations. A constant electric field is applied to charged biomolecules in solution, attracting them to an oppositely charged electrode, which is also used as a SERS substrate. Within 5 min, we observed that the SERS signal of 10 fM adenine was amplified to the level of the signal of non-preconcentrated 1 microM adenine (sensitivity improvement by 8 orders of magnitude) and the method was effective over a wide range of concentrations (10 fM to 1 microM). The signals were further amplified under stronger electric field and longer application: The increase of the signal intensity was observed to be 51 times at -0.6 V cm(-1) after 25 min. The effectiveness of this method allows the creation of label-free, target-specific, and highly sensitive monitoring applications.

Publication types

  • Evaluation Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adenine / analysis*
  • Electrophoresis / methods*
  • Sensitivity and Specificity
  • Spectrum Analysis, Raman / methods*
  • Surface Properties


  • Adenine