Application of graphene-pyrenebutyric acid nanocomposite as probe oligonucleotide immobilization platform in a DNA biosensor.

Xuan Zhang, Feng Gao, Xili Cai, Meixia Zheng, Fei Gao, Shulian Jiang, Qingxiang Wang

Index: Mater. Sci. Eng. C. Mater. Biol. Appl. 33(7) , 3851-7, (2013)

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Abstract

A stable and uniform organic-inorganic nanocomposite that consists of graphene (GR) and pyrenebutyric acid (PBA) was obtained by ultrasonication, which was characterized by scanning electron microscopy (SEM) and UV-vis absorption spectra. The dispersion was dropped onto a gold electrode surface to obtain GR-PBA modified electrode (GR-PBA/Au). Electrochemical behaviors of the modified electrode were characterized by cyclic voltammetry and electrochemical impedance spectroscopy using [Fe(CN)6](3-/4-) as the electroactive probe. A novel DNA biosensor was constructed based on the covalent coupling of amino modified oligonucleotides with the carboxylic group on PBA. By using methylene blue (MB) as a redox-active hybridization indicator, the biosensor was applied to electrochemically detect the complementary sequence, and the results suggested that the peak currents of MB showed a good linear relationship with the logarithm values of target DNA concentrations in the range from 1.0×10(-15) to 5.0×10(-12) M with a detection limit of 3.8×10(-16) M. The selectivity experiment also showed that the biosensor can well distinguish the target DNA from the non-complementary sequences.Copyright © 2013 Elsevier B.V. All rights reserved.