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Issue 21, 2017
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Target-induced duplex–triplex transition for ratiometric detection of adenosine triphosphate

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Abstract

Compared with conventional binding pairs of antigens and antibodies, facile chemical synthesis and generally impressive target selectivity make aptamers an ideal recognition tool for designing various biosensors. Herein, we developed a new ratiometric aptamer sensor based on an aptamer/target-binding-induced duplex–triplex transition. This sensor is composed of a capture strand (CS) modified with a BHQ2 at the 3′ end, a triplex-forming middle strand (MS) modified with TAMRA at the 3′ end, and a target-specific aptamer strand (AS) modified with FAM at the 5′ end. In the absence of analyte, the CS probe could hybridize with both the AS probe at the 3′ end and the MS probe at the 5′ end. As BHQ2 and FAM were in close proximity, the mixed solution showed low FAM fluorescence and high TAMRA fluorescence. After introducing the target molecule ATP, target/aptamer binding split from the duplex helix and liberated the end of the CS probe to fold back and form a triplex helix. Meanwhile, the FAM fluorescence could be recovered, and the TAMRA fluorescence could be quenched due to the close proximity of TAMRA and BHQ2. The intensity ratio (FFAM/FTAMRA) was linear for ATP concentrations of 0.1–10 μM in buffer solution. The detection limit was determined as 65 nM, based on three times the signal-to-noise ratio. The sensor was also applied to ATP sensing in bovine serum, obtaining a good recovery and demonstrating the practicality of this ratiometric aptamer sensor.

Graphical abstract: Target-induced duplex–triplex transition for ratiometric detection of adenosine triphosphate

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Publication details

The article was received on 25 Feb 2017, accepted on 12 May 2017 and first published on 12 May 2017


Article type: Paper
DOI: 10.1039/C7AY00507E
Citation: Anal. Methods, 2017,9, 3244-3248
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    Target-induced duplex–triplex transition for ratiometric detection of adenosine triphosphate

    S. Yao, Y. Gao, W. Wang, D. Ni, K. Zhang, L. Li, J. Du and X. Cui, Anal. Methods, 2017, 9, 3244
    DOI: 10.1039/C7AY00507E

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