Tetrahedral DNA probe coupling with hybridization chain reaction for competitive thrombin aptasensor

Publication date: 15 February 2018
Source:Biosensors and Bioelectronics, Volume 100
Author(s): Ying-Xu Chen, Ke-Jing Huang, Liu-Liu He, Yi-Han Wang
A novel competitive aptasensor for thrombin detection is developed by using a tetrahedral DNA (T-DNA) probe and hybridization chain reaction (HCR) signal amplification. Sulfur and nitrogen co-doped reduced graphene oxide (SN-rGO) is firstly prepared by a simple reflux method and used for supporting substrate of biosensor. Then, T-DNA probe is modified on the electrode by Au-S bond and a competition is happened between target thrombin and the complementary DNA (cDNA) of aptamer. The aptamer binding to thrombin forms an aptamer-target conjugate and make the cDNA remained, and subsequently hybridizes with the vertical domain of T-DNA. Finally, the cDNAs trigger HCR, which results in a great current response by the catalysis of horseradish peroxidase to the hydrogen peroxide + hydroquinone system. For thrombin detection, the proposed biosensor shows a wide linearity range of 10^–13–10⁻⁸M and a low detection limit of 11.6fM (S/N = 3), which is hopeful to apply in biotechnology and clinical diagnosis.



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