A facile DNA strand displacement reaction sensing strategy of electrochemical biosensor based on N-carboxymethyl chitosan/molybdenum carbide nanocomposite for microRNA-21 detection.

Author(s) Tian, L.; Qi, J.; Ma, X.; Wang, X.; Yao, C.; Song, W.; Wang, Y.
Journal Biosens Bioelectron
Date Published 2018 Dec 30
Abstract

Herein, we report a facile enzyme-free microRNA (miRNA) target-triggered strand displacement reaction (SDR) amplification strategy with ferrocene (Fc) as a signal molecule to fabricate a two-dimensional electroactive molybdenum carbide (MoC)-based biosensor. In the presence of miRNA-21, SDR was initiated and many hairpin DNA1 (HDNA1) and hairpin DNA2 (HDNA2) duplexes, which could be captured by probe DNA leading the Fc-modified HDNA2 close to the electrode surface, were produced continuously. MiRNA-21 could be detected by monitoring the redox signal of Fc. The prepared N-carboxymethyl chitosan/MoC nanocomposite featured excellent conductivity, great dispersion, and multiple functional groups (amine groups). When the nanocomposite was introduced to a miRNA biosensor electrode interface to ensure its strong connection to the DNA probe, the developed miRNA-21 biosensor demonstrated a reliable linear range of 1.0 fM to 1.0 nM with a detection limit of 0.34 fM and showed good selectivity, reproducibility, and stability. The biosensor was employed to detect miRNA-21 in human serum samples, and it showed great potential in the early clinical diagnosis of various genetic diseases.

DOI 10.1016/j.bios.2018.09.037
ISSN 1873-4235
Citation Tian L, Qi J, Ma X, Wang X, Yao C, Song W, et al. A facile DNA strand displacement reaction sensing strategy of electrochemical biosensor based on N-carboxymethyl chitosan/molybdenum carbide nanocomposite for microRNA-21 detection. Biosens Bioelectron. 2018;122:43-50.

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