Min Huang,Hanying Li,Hanping He,Xiuhua Zhang,Shengfu Wang
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.
In this paper, a novel electrochemical sensor was developed for the rapid detection of G-G mismatched DNA based on hexaammineruthenium(III) chloride ([Ru(NH 3 ) 6 ]C l3 ) as a redox indicator. The sensor platform was constructed by immobilizing small molecules (NC-linker) on the gold electrode via amide bonds. The as-prepared NC-linker as the nucleic acids recognition molecule can interact with the G base of DNA. After the sensor was incubated with G-G mismatched DNA, the double-stranded DNA (dsDNA) acted as carriers of the signal tags-[Ru(NH3)6]Cl3, which resulted in a remarkable electrochemical signal. More binding of [Ru(NH 3 ) 6 ]C l3 led to increases of the electrochemical signal. Other mismatched DNA produced only a low response, as well as complementary DNA. Thus G-G mismatched DNA can be easily discriminated from other mismatched and complementary DNA based on the sensor. Furthermore, the method was simple, rapid and repeatable for the detection of G-G mismatched DNA. The selective detection of target dsDNA was achieved by a relative current ratio of the target and control DNA. These results demonstrated that this strategy could provide great promise for the rapid and specific detection of other sequence-specific DNA.
危险品化学品经营许可证（带存储）