Ultrasensitive Electrochemical Detection of MicroRNA Based on an Arched Probe Mediated Isothermal Exponential Amplification

Abstract

In this work, a simple and label-free electrochemical biosensor is developed for microRNA (miRNA) detection on the basis of an arched probe mediated isothermal exponential amplification reaction (EXPAR). The arched probe assembled on the electrode surface consists of two strands that are partially complementary to each other at both ends. The target can hybridize with the complementary sequence of the arched structure, leading to the cleavage of the probe. The strand fixed on the surface of the electrode self-assembles, in the presence of hemin, to G-quadruplex unit, yielding electrochemical signals. The other strand liberated into the solution triggers the EXPAR to recycle and regenerate targets. This method exhibits ultrahigh sensitivity toward miRNA with detection limits of 5.36 fM and a detection range of 3 orders of magnitude. The biosensor is capable of discriminating a single-nucleotide difference between concomitant miRNA and performs well in analyzing crude extractions from cancer cell lines.

Highly Efficient Intramolecular Electrochemiluminescence Energy Transfer for Ultrasensitive Bioanalysis of Aflatoxin M1

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Electrochemical Biosensors for miRNA Detection

“…The achievement of high sensitivity and selectivity requires maximization of the hybridization efficiency and minimization of nonspecific adsorption, respectively. Several kinds of electrode surface have been investigated as electrochemical transducers in genosensor development: glassy carbon (Liu et al 2014a), screen-printed carbon (Bettazzi et al 2013), screen-printed gold (Farabullini et al 2007;Bettazzi et al 2008;Voccia et al 2015), gold (Yu et al 2014), and ITO electrodes (Patel et al 2013). Generally, the use of disposable electrodes that avoid the regeneration step appears to be the most promising approach (Laschi et al 2006).…”

miRNA Optical Detection

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