A novel label-free electrochemical microRNA biosensor using Pd nanoparticles as enhancer and linker

Abstract

In this paper, a novel, label-free amperometric biosensor for the detection of microRNA-155 based on the conductive self-assembled multilayer comprised of Nafion, thionine (Thi) and Pd nanoparticles was successfully prepared. Nafion was firstly dropped on to a bare glass carbon electrode. Then Thi was absorbed by the cation exchanger Nafion. Furthermore, a Pd nanoparticles layer which was used to immobilize target biomolecules was constructed by the amino group of Thi as linker. Moreover, the proposed biosensor showed excellent electrocatalytic activity towards H(2)O(2) and enhanced the current response of the biosensor. Cyclic voltammetry was used for the characterization and electrochemical properties of the stepwise self-assembly process of the biosensor, and scanning electron microscopy was used for observing the microstructure of the modified film. Using microRNA-155 as a model, the resulting biosensor presented high sensitivity, good stability and a broad linear response from 5.6 to 5.6 × 10(5) pM with the detection limit of 1.87 pM under optimization of the assay conditions.

Nanomaterials-Based Sensing Strategies for Electrochemical Detection of MicroRNAs

“…The use of metal nanoparticles (e.g., Ag, Pd) as catalysts is analogous to the way of enzymes and might overcome some of the problems related to the inherent thermal and environmental instability of the enzyme [49,50]. For example, silver nanoclusters (Ag-NCs) display efficient catalytic property toward H 2 O 2 reduction.…”

An Exonuclease I-Based Quencher-Free Fluorescent Method Using DNA Hairpin Probes for Rapid Detection of MicroRNA

“…Device-based analytical strategies mainly include electrochemical sensors and MEMS [14,15]. Methods-based approaches mainly include fluorescence, colorimetric, and luminescence assays [16,17,18,19,20,21,22,23,24,25,26,27,28]. Among these, the fluorometric method is an excellent choice for the quantitative detection of miRNAs due to its high sensitivity and convenience of operation.…”

Ultrasensitive strategy based on PtPd nanodendrite/nano-flower-like@GO signal amplification for the detection of long non-coding RNA

“…However, thionine is difficult to directly bind to HULC for no related residues in nucleic acids. Therefore, a series of labeling methods that indirectly absorb other materials, such as graphene (Lai et al, 2014;Li et al, 2015), electrode coatings (Wu et al, 2013) and SWCNT (Gong et al, 2008;He et al, 2006), have been developed. But the high signal background is a notable drawback and may hinder the specificity of detection.…”