An electrochemical impedance sensor for simple and specific recognition of G–G mismatches in DNA

[摘要] The sequence-specific recognition of SNPs is important for disease diagnosis and human gene therapy. In this work, a simple sensor based on electrochemical impedance spectroscopy (EIS) was developed for the highly sensitive and specific detection of G–G mismatches in dsDNA using a small molecule-modified gold electrode. After the electrochemical impedance sensor was incubated with G–G mismatched dsDNA, its charge-transfer resistance (Rct) increased significantly. Meanwhile, only a small increase in Rct values was observed for dsDNA with other base mismatches and for complementary dsDNA. Importantly, G–G mismatched dsDNA was selectively detected based on differences in charge transfer resistance (ΔRct) even in the presence of other DNA and ct-DNA. Under optimal experimental conditions, the established EIS sensor was used to quantify G–G mismatched dsDNA based on the linear relationship between ΔRct and the logarithm of the concentration of G–G mismatched dsDNA from 1 nM to 1 μM with a detection limit of 0.3 nmol L−1. This sensing strategy is a potential alternative tool for measuring G–G mismatched DNA for the diagnosis and early clinical detection of genetic diseases.

[学科分类] 分析化学