title: Aptamer-based electrochemical biosensor for interferon gamma detection.
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.
authors.affiliation: Department of Biomedical Engineering, University of California, Davis, California, USA.
authors.forename: Ying
authors.initials: Y
authors.lastname: Liu
authors.forename: Nazgul
authors.initials: N
authors.lastname: Tuleouva
authors.forename: Erlan
authors.initials: E
authors.lastname: Ramanculov
authors.forename: Alexander
authors.initials: A
authors.lastname: Revzin
mesh_terms: D052157:Aptamers, Nucleotide / Q000737:chemistry*; D015374:Biosensing Techniques / Q000379:methods*; D001798:Blood Proteins / Q000737:chemistry; D055664:Electrochemical Techniques / Q000379:methods*; D004566:Electrodes; D004791:Enzyme Inhibitors / Q000737:chemistry; D006046:Gold / Q000737:chemistry; D006801:Humans; D007371:Interferon-gamma / Q000032:analysis*; D008751:Methylene Blue / Q000737:chemistry; D010084:Oxidation-Reduction; D011994:Recombinant Proteins; D020349:Surface Plasmon Resonance
chemical_list: D052157:Aptamers, Nucleotide; D001798:Blood Proteins; D004791:Enzyme Inhibitors; D011994:Recombinant Proteins; D006046:Gold; D007371:Interferon-gamma; D008751:Methylene Blue
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