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

Hansang Cho, Brian Lee, Gang L. Liu, Ajay Agarwal, Luke P. Lee

Research output: Contribution to journalArticlepeer-review

119 Scopus citations


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 μM adenine (sensitivity improvement by 8 orders of magnitude) and the method was effective over a wide range of concentrations (10 fM to 1 μM). 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.

Original languageEnglish
Pages (from-to)3360-3363
Number of pages4
JournalLab on a Chip
Issue number23
StatePublished - 2009


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