Title
Proximity hybridization triggered hemin/G-quadruplex formation for construction a label-free and signal-on electrochemical DNA sensor
Author
Fenglei Gao, Taotao Fan, Jing Wu, Sha Liu, Yan Du, Yao Yao, Fuyi Zhou, Yu Zhang, Xianjiu Liao, Deqin Geng
Year
2017
Journal
Biosensors and Bioelectronics
Abstract
We describe a novel label-free and signal-on electrochemical DNA sensing platform via proximity hybridization triggered hemin/G-quadruplex formation based on the direct electron transfer of hemin. The thiolated modified G-DNA1 was first immobilized onto the Au electrode surface. In the presence of target DNA, Y-junction-structure ternary complex can be formed to trigger the proximity assembly of G-DNA1, hemin, and G-DNA2, which leads to the formation of hemin/G-quadruplex for generation an amplified electrochemical signal by differential pulse voltammetry. The observed signal gain was sufficient to achieve a demonstrated detection limit of 54 fM, with a wide linear dynamic range from 10−13 to 10−9 M and discriminated mismatched DNA from perfect matched target DNA with a high selectivity. Benefiting from the one step proximity dependent hemin/G-quadruplex formation, the assay method is extremely simple and can be carried out within 40 min. The advantages of free of any label conjugation step, and versatility make it a promising candidate for point-of-care testing and commercial application.
Instrument
J-815
Keywords
Circular dichroism, DNA structure, Biochemistry, Materials