Antibodies Directed to RNA/DNA Hybrids: An Electrochemical Immunosensor for MicroRNAs Detection using Graphene-Composite Electrodes

Abstract

We report a simple and sensitive label-free immunosensor for detection of microRNAs (miRNA) based on a conducting polymer/reduced graphene oxide-modified electrode to detect miR-29b-1 and miR-141. Square wave voltammetry is used to record the redox signal. Current increases upon hybridization (signal on) from 1 fM to 1 nM of target miRNA. The limit of quantification is ca. 5 fM. The sensor exhibits high selectivity as it distinguishes mismatch. To double-check its selectivity, two specific RNA-DNA antibodies recognizing miRNA-DNA heteroduplexes, antipoly(A)-poly(dT) and anti-S9.6, were used. The antibody complexation with the hybrid leads to a current decrease that confirms the presence of miRNA, down to a concentration of 8 fM. The antibody-hybrid complex can be then dissociated by adding miRNA-DNA hybrids in solution, causing a shift-back on the signal, i.e., an increase in the current density (signal-on). This On-Off-On detection sequence was used as a triple verification to increase the reliability of the results.

Electrolytic Gated Organic Field-Effect Transistors for Application in Biosensors—A Review

“…Another issue that must be addressed is their high subthreshold swing, typically of several hundreds of millivolts, which impede their sensitivity. A strategy may be to switch from classical OSC to graphene-based materials, e.g., graphene or reduced graphene oxide, which has already been reported [33][34][35][36][37][38][39][40][41][42][43][44][45][46], but this will not be discussed here. Readers who are interested in grapheme-based EGOFETs may report on the review from Yan et al, 2013, which dealt with graphene-based transistors for biological sensors [47].…”

An electrochemical ELISA-like immunosensor for miRNAs detection based on screen-printed gold electrodes modified with reduced graphene oxide and carbon nanotubes

“…Many publications have described application of GO and RGO for DNA or peptide detection (previously cited articles, and Wu et al, 2012;Feng et al, 2013;Huang et al, 2012;Dong et al, 2012a). However, miRNAs detection has been less described and mainly based on fluorescence quenching on graphene; few publications investigated electrochemical transduction on these materials (Cui et al, 2012;Yin et al, 2012;Tran et al, 2013a). miRNAs are a class of small non-protein-coding single strand ribonucleic acid molecules (RNAs) of 18 to 30 nucleotides which play crucial roles in cell proliferation, differentiation and apoptosis.…”

Intercalation of quantum dots as the new signal acquisition and amplification platform for sensitive electrochemiluminescent detection of microRNA

“…Up to now, with the great achievements of nanotechnology, nanomaterials are widely used in various miRNA detection schemes due to their fascinating properties in connection to colorimetric [17], photoelectrochemical (PEC) [18], electrochemical (EC) [19][20][21][22] and electrochemiluminescent (ECL) [23][24][25] techniques for signal transduction. Among the popular nanomaterials, semiconductive quantum dots (QDs) have emerged as excellent candidates in biosensor applications attributing to their specific optical and EC properties, which can act as signal tags to trace the recognition events through the target-induced fluorescent or ECL emission variation, or the current change of the metal ions released from the acid-dissolved QDs [24].…”