A rapid electrochemical biosensor based on an AC electrokinetics enhanced immuno-reaction

I. Fang Cheng, Hsiao Lan Yang, Cheng Che Chung, Hsien Chang Chang

Research output: Contribution to journalArticlepeer-review

34 Citations (Scopus)


Fluorescent labelling and chromogenic reactions that are commonly used in conventional immunoassays typically utilize diffusion dominated transport of analytes, which is limited by slow reaction rates and long detection times. By integrating alternating current (AC) electrokinetics and electrochemical impedance spectroscopy (EIS), we construct an immunochip for rapid, sensitive, and label-free detection. AC electroosmosis (ACEO) and positive dielectrophoresis (DEP), induced by a biased AC electric field, can rapidly convect and trap the analyte onto an EIS working electrode within a few minutes. This allows the change of electron-transfer resistance (ΔRet) caused by the antibody-antigen (IgG-protein A) binding to be measured and quantified in real time. The measured impedance change achieves a plateau after electrokinetic concentration for only 90 s, and the detection limit is able to reach 200 pg ml-1. Compared to the conventional incubation method, the electrokinetics-enhanced method is approximately 100 times faster in its reaction time, and the detection limit is reduced by 30 times. The ΔR et of the positive response is two orders of magnitude higher than the negative control, demonstrating excellent specificity for practical applications.

Original languageEnglish
Pages (from-to)4656-4662
Number of pages7
Issue number16
Publication statusPublished - 2013 Aug 21

All Science Journal Classification (ASJC) codes

  • Analytical Chemistry
  • Biochemistry
  • Environmental Chemistry
  • Spectroscopy
  • Electrochemistry


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