title: 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.
authors.affiliation: Hubei Collaborative Innovation Center for Advanced Organic Chemical Materials, Hubei University, Youyi Road 368, Wuchang, Wuhan, Hubei 430062, PR China. hehanping@hubu.edu.cn.
authors.forename: Hanping
authors.initials: H
authors.lastname: He
authors.forename: Xiaoqian
authors.initials: X
authors.lastname: Peng
authors.forename: Min
authors.initials: M
authors.lastname: Huang
authors.forename: Gang
authors.initials: G
authors.lastname: Chang
authors.forename: Xiuhua
authors.initials: X
authors.lastname: Zhang
authors.forename: Shengfu
authors.initials: S
authors.lastname: Wang
mesh_terms: D058266:Dielectric Spectroscopy / Q000295:instrumentation*; D004566:Electrodes; D006046:Gold / Q000737:chemistry*; D057230:Limit of Detection; D018911:Trinucleotide Repeats
chemical_list: D006046:Gold