Aptamer-based electrochemical biosensor for interferon gamma detection

Anal Chem. 2010 Oct 1;82(19):8131-6. doi: 10.1021/ac101409t.

Abstract

In this paper, we describe the development of an electrochemical DNA aptamer-based biosensor for detection of interferon (IFN)-γ. A DNA hairpin containing IFN-γ-binding aptamer was thiolated, conjugated with methylene blue (MB) redox tag, and immobilized on a gold electrode by self-assembly. Binding of IFN-γ caused the aptamer hairpin to unfold, pushing MB redox molecules away from the electrode and decreasing electron-transfer efficiency. The change in redox current was quantified using square wave voltammetry (SWV) and was found to be highly sensitive to IFN-γ concentration. The limit of detection for optimized biosensor was 0.06 nM with linear response extending to 10 nM. This aptasensor was specific to IFN-γ in the presence of overabundant serum proteins. Importantly, the same aptasensor could be regenerated by disrupting aptamer-IFN-γ complex in urea buffer and reused multiple times. Unlike standard sandwich immunoassays, the aptasensor described here allowed one to detect IFN-γ binding directly without the need for multiple washing steps and reagents. An electrochemical biosensor for simple and sensitive detection of IFN-γ demonstrated in this paper will have future applications in immunology, cancer research, and infectious disease monitoring.

Publication types

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

MeSH terms

  • Aptamers, Nucleotide / chemistry*
  • Biosensing Techniques / methods*
  • Blood Proteins / chemistry
  • Electrochemical Techniques / methods*
  • Electrodes
  • Enzyme Inhibitors / chemistry
  • Gold / chemistry
  • Humans
  • Interferon-gamma / analysis*
  • Methylene Blue / chemistry
  • Oxidation-Reduction
  • Recombinant Proteins
  • Surface Plasmon Resonance

Substances

  • Aptamers, Nucleotide
  • Blood Proteins
  • Enzyme Inhibitors
  • Recombinant Proteins
  • Gold
  • Interferon-gamma
  • Methylene Blue