An electrochemical DNA sensor based on polyaniline/graphene: high sensitivity to DNA sequences in a wide range

Abstract

A label-free electrochemical DNA sensor was fabricated by deposition of polyaniline and pristine graphene nanosheet (P/G(ratios)) composites in different mass ratios, DNA probe and bovine serum albumin (BSA) layer by layer on the surface of a glassy carbon electrode (GCE). Electrochemical impedance spectroscopy (EIS) was employed to monitor every step of fabrication of P/G(ratio)-based DNA sensors and to evaluate the detection results in terms of the hybridization of complementary DNA, mutant DNA and non-complementary DNA. The results illustrate that the P/G(ratio)-based DNA sensor could highly efficiently detect complementary DNA from 0.01 pm to 1 μm and discriminate single-nucleotide polymorphisms (SNPs). In the process of detection, double-stranded DNA (dsDNA), resulting from hybridization of a DNA probe, escaping from or remaining on the sensor surface, was monitored by changing the ratio of polyaniline (PANI) to graphene, which was decided by the competition between the electrostatic interaction and Brownian motion.

Employing Label‐free Electrochemical Biosensor Based on 3D‐Reduced Graphene Oxide and Polyaniline Nanofibers for Ultrasensitive Detection of Breast Cancer BRCA1 Biomarker

“…Two-dimensional (2D) graphene offers large surface area for immobilization of biomolecules and fast electron transfer rate [30][31][32]. Single-stranded DNA (ssDNA) can be stably immobilized on graphene surface through π-π stacking interaction between the conjugated π bonds of nucleotide bases and the hexagonal units of graphene [33,34], which is beneficial for electrochemical biosensing applications. Additionally, more and more attention has been paid to three-dimensional (3D) graphene, because the 3D macroporous structures are able to provide more sufficient adsorption space and contact area between electrolyte and electrode to further enhance the property and broaden the applications of graphene [35,36].…”

The long-range effect induced by untying hydrogen bonds for single cell test using SECM

“…For 3-MPA SAM substrate electrode, both current of anodic peak (I pa ) and cathodic peak (I pc ) have a little decrease and the separation potential between anodic peak and cathodic peak (ΔE p ) becomes bigger than the bare Au substrate electrode. In the experiment of EIS, the Randles equivalent circuit[28] was used to fit EIS data and determine the charge transfer resistance (R ct ). The EIS curves show that the R ct value of 3-MPA SAM electrode (282.1 ohm) is slightly higher than the bare electrode (254.6 ohm).…”

Polymer–Graphene Nanocomposite Materials for Electrochemical Biosensing

“…Du et al, on the other hand, reported a DNA biosensor based on electrochemically reduced GO and PANI nanofibers, with noncovalently assembled oligonucleotide probes and [Ru(NH 3 ) 6 )] 3+ as a redox marker. More recently, Zheng et al prepared pristine graphene PANI nanocomposites at various mass ratios, via solution mixing and casting, followed by oligonucleotide probe adsorption and bovine serum albumin adsorption, aimed at minimizing nonspecific signal . By tuning the graphene PANI mass ratio it was possible to adjust the detection limit and dynamic range.…”