Gold nanoparticle-engineered electrochemical aptamer biosensor for ultrasensitive detection of thrombin.

Ying Chen, Junyi Xiang, Bin Liu, Zhengbo Chen, Xia Zuo

Analytical methods : advancing methods and applications 2020 Aug 07

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In order to obtain a lower detection limit in electrochemical detection, the choice of signal amplification strategy is of great importance. In this work, we describe an electrochemical sandwich aptasensor based on a signal amplification system involving two thrombin (TB) aptamers (TBA1 and TBA2), gold nanoparticles (AuNPs) as aptamer carriers, and [Ru(NH3)6]3+ for signal conversion. In the presence of the target thrombin, TBA1 and TBA2 specifically bind to TB, and the TBA1-TB-TBA2 complexes cause the formation of a sandwich structure, meaning more [Ru(NH3)6]3+ can be adsorbed on the negatively charged phosphate backbone of the aptamers, resulting in an increase in the differential pulse voltammetry (DPV) current. Under optimal conditions, the aptasensor exhibited a linear range of 1 fM to 6 pM and a limit of detection of 0.1429 fM (S/N = 3) for TB. The proposed aptasensor displayed an excellent selectivity and reproducibility. Importantly, the aptasensor was capable of detecting TB in serum samples successfully.

Citation

Ying Chen, Junyi Xiang, Bin Liu, Zhengbo Chen, Xia Zuo. Gold nanoparticle-engineered electrochemical aptamer biosensor for ultrasensitive detection of thrombin. Analytical methods : advancing methods and applications. 2020 Aug 07;12(29):3729-3733