Carbon Nanotube-Polyamidoamine Dendrimer Hybrid-Modified Electrodes for Highly Sensitive Electrochemical Detection of MicroRNA24

Abstract

A simple and ultrasensitive microRNA (miRNA) electrochemical biosensor employing multiwalled carbon nanotube (MWCNT)-polyamidoamine (PAMAM) dendrimer and methylene blue (MB) redox indicator is reported in this work. The assay utilizes a glass carbon (GC) electrode modified with MWCNT-PAMAM, on which the oligonucleotide capture probes are immobilized. The electrochemical detection of miRNAs is completed by measuring the reduction signal change of MB before and after the probe hybridization with target miRNA (miRNA24 is used as a model case). The MWCNT-PAMAM/GC electrode shows greatly enhanced signal to MB reduction in contrast to bare GC electrode. The functionalization of MWCNT with PAMAM maintains the electrochemical property of MWCNT to MB reduction but minimizes the undesired adsorption of MB on the MWCNT surface. The effect of experimental variables on the miRNA detection is investigated and optimized. A detection limit of 0.5 fM and a linear peak current density-concentration relationship up to 100 nM are obtained following 60 min hybridization. The proposed assay is successfully used to detect miRNA24 in total RNA sample extracted from HeLa cells.

Biophysical and biological contributions of polyamine-coated carbon nanotubes and bidimensional buckypapers in the delivery of miRNAs to human cells

“…26 BPs are randomly entangled and densely packed CNT networks, which have been employed in retina and iris pigment epithelial transplantation 27 as actuators, 28 biosensors, 29 carriers for drug delivery 30 and finally as scaffolds for tissue engineering. 31 Although few studies have characterized the properties of BPs on cell adhesion, cell response and cytotoxicity [32][33][34] and proposed the use of BPs in medical applications, [35][36][37] the use of BPs as transfecting agents for nucleic acids has never been proposed. Therefore, our systematic investigation of the biophysical and biological properties of bidimensional CNT-based drug delivery systems is not only original and innovative but also very useful for a further extension of this work aimed at employing BPs as scaffolds or supports for cell growth.…”

Emerging Biosensing Approaches for microRNA Analysis

“…108 Similar approaches used methylene blue as a label. 109 Methylene blue has a higher affinity for ssDNA versus miRNA hybrids. miRNA binding therefore decreased the electrochemical for methylene blue, as detected via voltammetry.…”

Sensitive detection of miRNA by using hybridization chain reaction coupled with positively charged gold nanoparticles

“…Traditional methods for miRNA detection mainly use the real-time reverse transcription polymerase chain reaction (RT-PCR)8, northern blotting9, miRNA array technology10 and different isothermal amplification techniques1112131415. Recently, a number of novel sensing approaches have been developed by using colorimetry16171819, fluorescence202122232425, electrochemiluminescence2627, electrochemistry28293031, and surface plasmon resonance (SPR)3233 as detection platform. Thereinto, colorimetric based methods have attracted great attention because of the merits of them including rapidness, simplicity and low cost34.…”