Sensitive Chronocoulometric Detection of miRNA at Screen-Printed Electrodes Modified by Gold-Decorated MoS₂Nanosheets

Abstract

Developing novel simple and ultrasensitive strategies for detecting microRNAs (miRNAs) is highly desirable because of their association with early cancer diagnostic and prognostic processes. Here a new chronocoulometric sensor, based on semiconducting 2H MoS2 nanosheets (MoS2 NSs) decorated with a controlled density of monodispersed small gold nanoparticles (AuNPs@MoS2), was fabricated via electrodeposition, for the highly sensitive detection of miRNA-21. The size and interparticle spacing of AuNPs were optimized by controlling nucleation and growth rates through the tuning of deposition potential and Au precursor concentration and by getting simultaneous feedback from morphological and electrochemical activity studies. The sensing strategy, involved the selective immobilization of the thiolated capture probe DNA (CP) at AuNPs and hybridization of CP to a part of the miRNA target, whereas the remaining part of the target was complementary to a signaling nonlabeled DNA sequence that served to amplify the target upon hybridization. Chronocoulometry provided precise quantification of nucleic acids at each step of the sensor assay by interrogating [Ru­(NH3)6]3+ electrostatically bound to phosphate backbones of oligonucleotides. A detailed and systematic optimization study demonstrated that the thinnest and smallest MoS2 NSs improved the sensitivity of the AuNP@MoS2 sensor, achieving an impressive detection limit of ≈100 aM, which is 2 orders of magnitude lower than that of a bare Au electrode and also enhanced the DNA–miRNA hybridization efficiency by 25%. Such an improved performance can be attributed to the controlled packing density of CPs achieved by their self-assembly on AuNPs, large interparticle density, small size, and intimate coupling between AuNPs and MoS2. Alongside the outstanding sensitivity, the sensor exhibited an excellent selectivity down to femtomolar concentrations, for discriminating a complementary miRNA-21 target in a complex system composed of different foreign targets including mismatched and noncomplementary miRNA-155. These advantages make our sensor a promising contender in the point of care miRNA sensor family for medical diagnostics.

Paper-Based Electrochemical Biosensors for Voltammetric Detection of miRNA Biomarkers Using Reduced Graphene Oxide or MoS2 Nanosheets Decorated with Gold Nanoparticle Electrodes

“…Hybridization efficiency (HE%) is calculated as evidence of the probe and miRNA hybridization efficacy in order to determine optimum conditions [49].…”

Electrochemical Detection of Solution Phase Hybridization Related to Single Nucleotide Mutation by Carbon Nanofibers Enriched Electrodes

“…Similarly, a 1.8 fold increase at R ct was observed in the presence of hybridization of the DNA probe with the wDNA target. According to the literature [50], the hybridization efficiency (HE%) provides information about the hybridization effectiveness. As a result, the hybridization efficiency (HE%) of our assay was also calculated and shown in Table S3.…”

“…In the present study, the impedimetric detection of the FV Leiden mutation was performed in contribution of the ZNA probe which resulted in a relatively shorter time (i.e., 30 min) and selectively in comparison to earlier studies in the literature without using any type of labeled probe [23,24,25,36,37,38,50,51,52,53,54,55,56,57]. Some of these studies related to the electrochemical detection of FV Leiden mutation was presented in Table S6.…”

Detection of urinary microRNA biomarkers using diazo sulfonamide-modified screen printed carbon electrodes

“…To date, the majority of SPCE-based miRNA-specic biosensors have used single channel electrodes to detect singular miRNA species. [27][28][29] These include a dual working surface system, 30 and a method using DNA nanostructures on an array of 16 gold electrodes. 31 By contrast, Erdem et al demonstrated multiplexed miRNA detection using a system containing 16 active surfaces with shared counter and reference electrodes, 32 and in one case used this set up to detect multiple miRNA species simultaneously.…”