Proximity hybridization triggered hemin/G-quadruplex formation for construction a label-free and signal-on electrochemical DNA sensor

Publication date: 15 October 2017
Source:Biosensors and Bioelectronics, Volume 96
Author(s): Fenglei Gao, Taotao Fan, Jing Wu, Sha Liu, Yan Du, Yao Yao, Fuyi Zhou, Yu Zhang, Xianjiu Liao, Deqin Geng
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 40min. The advantages of free of any label conjugation step, and versatility make it a promising candidate for point-of-care testing and commercial application.



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