Issue 21, 2014

An electrochemical impedance sensor based on a small molecule modified Au electrode for the recognition of a trinucleotide repeat

Abstract

A small molecule modified sensor was developed for the detection of XGG trinucleotide repeats (X = C, T) by electrochemical impedance spectroscopy. The sensor (NCD/MPA/Au) was fabricated by immobilizing the nucleic acid recognition molecule (NCD) on the surface of a gold electrode through a condensation reaction between the amino-terminal end of the NCD linker and carboxylic groups in 3-mercaptopropionic acid that were self-assembled on the electrode surface. After the sensor was incubated with trinucleotide repeats, electrochemical impedance spectroscopy was performed using [Fe(CN)6]3−/4− as redox marker ions. XGG repeats (X = C, T) could be selectively detected based on the differences in charge transfer resistance (ΔRct) even in the presence of other trinucleotide repeats. The relationship between ΔRct and lg [concentration of CGG repeats] for the sensor was linear from 1 nM to 1 μM, enabling the quantification of the number of repeats. The electrochemical impedance sensor provides a simple and rapid method to detect trinucleotide repeats without requiring labelling and immobilizations of DNA, making it promising for the early diagnosis of neurodegenerative diseases; the sensor may be further extended to the detection of other special sequences of DNA.

Graphical abstract: An electrochemical impedance sensor based on a small molecule modified Au electrode for the recognition of a trinucleotide repeat

Supplementary files

Article information

Article type
Paper
Submitted
12 May 2014
Accepted
10 Aug 2014
First published
11 Aug 2014

Analyst, 2014,139, 5482-5487

Author version available

An electrochemical impedance sensor based on a small molecule modified Au electrode for the recognition of a trinucleotide repeat

H. He, X. Peng, M. Huang, G. Chang, X. Zhang and S. Wang, Analyst, 2014, 139, 5482 DOI: 10.1039/C4AN00853G

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