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A rolling circle amplification-assisted DNA walker triggered by multiple DNAzyme cores for highly sensitive electrochemical biosensing

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Abstract

DNA walkers from monopodial to multipedal types have usually one cleavage site to power the walking system along with the track. Herein, a multipedal DNA walker (m-DNA walker) with multiple DNAzyme cores was constructed with the assistance of rolling circle amplification (RCA) for highly sensitive electrochemical biosensing. Firstly, a three-component DNA complex as a swing strand was prepared by integrating a padlock, an RCA primer and a block DNA as a recognition element in the DNA walker system. After ferrocene-labeled track DNA (trDNA) and capture DNA were fixed on a gold electrode, the three-component DNA complex was imported onto the electrode as a swing arm to form a m-DNA walker. In the presence of target DNA and a RCA kit, the block was displaced from the complex and RCA was initiated to form multiple DNAzyme strands. Upon hybridization with trDNA, the m-DNA walker was motivated by the cleavage of multiple DNAzyme cores in the presence of manganese ions to free signal molecules. Under the optimal circumstances, the electrochemical m-DNA walker showed a linear range from 1.0 fM to 1.0 nM with a detection limit of 0.28 fM. Moreover, the m-DNA walker demonstrated a rapid cleavage rate and a low ratio of the swing strand to the track, which is more excellent than a single foot walker and a bipedal DNA walker. The practicality of the proposed strategy was also confirmed by detecting target DNA in 10% human serum, showing promising applications in clinical diagnosis.

Graphical abstract: A rolling circle amplification-assisted DNA walker triggered by multiple DNAzyme cores for highly sensitive electrochemical biosensing

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Publication details

The article was received on 03 Oct 2018, accepted on 13 Nov 2018 and first published on 16 Nov 2018


Article type: Paper
DOI: 10.1039/C8AN01892H
Citation: Analyst, 2019, Advance Article
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    A rolling circle amplification-assisted DNA walker triggered by multiple DNAzyme cores for highly sensitive electrochemical biosensing

    S. Wang, Y. Ji, H. Fu, H. Ju and J. Lei, Analyst, 2019, Advance Article , DOI: 10.1039/C8AN01892H

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