Electrochemical determination of microRNA-21 based on bio bar code and hemin/G-quadruplet DNAenzyme

Abstract

A simple and novel microRNA (miRNA) biosensor was developed using DNA-Au bio bar code (DNA-Au) and G-quadruplex-based DNAenzyme. DNA-Au increased the amount of miRNA-21 participating in hybridization. Hemin/G-quadruplex DNAenzyme significantly improved the catalysis of H(2)O(2) by oxidation of hydroquinone, resulting in an obvious reduction current of benzoquinone for miRNA-21 indirect detection. Under optimum conditions, the linear relationship between miRNA-21 concentration and reduction response was obtained with the detection limit of 0.006 pM, which showed a good sensitivity. Besides, selectivity of the biosensor was investigated by detecting the base mismatched miRNAs. This proposed method was further applied to detect miRNA-21 extracted from human hepatocarcinoma BEL-7402 cells and human mastocarcinoma MCF-7 cells. The influence of bisphenol A (BPA) on the expression of miRNA-21 in cells was also investigated. The biosensor performs well in practical applications, which suggests it may provide a new platform for gene diagnosis.

Emerging Biosensing Approaches for microRNA Analysis

“…Strategies to induce a change in charge transfer include the enzymatic turnover of an insulating polymer via DNAzymes, 143 hemin conjugated carboxylic graphene 144 and DNAzyme functionalized gold nanoparticles 145 . These assays reported detection limits ranging from 100s of aM to 10 of fM LODs with dynamic ranges of 1.5, 3.5, and 4.5 orders, respectively.…”

Detection of microRNA in clinical tumor samples by isothermal enzyme-free amplification and label-free graphene oxide-based SYBR Green I fluorescence platform

“…Three kinds of tumor cell lines (A549, HepG2 and MCF-7) with high miRNA-21 expression levels (Calin et al, 2004;Iorio et al, 2005;Wang et al, 2011;Meng et al, 2013) are selected to investigate the capacity of our method for detection of tumor cells. Different concentrations of cells confirmed by cell counting range from 10 2 cells to 10 6 cells, were treated by the total RNA extraction kit, and then followed by EFA and fluorescence detection.…”

Nanomaterials-Based Sensing Strategies for Electrochemical Detection of MicroRNAs

“…A detection limit of 3.96 pM and a dynamic range of 5 pM–5 nM were obtained. Furthermore, they found that the hemin-G-quadruplex on AuNPs can significantly promote the catalysis of H 2 O 2 by oxidation of hydroquinone; this led to an obvious reduction current of benzoquinone [38]. This method could be used to detect miRNAs with a detection limit of 6 fM and a dynamic range of 0.01–500 pM.…”