Electrochemical DNA biosensor based on IL‐modified MWNTs electrode prepared by radiation‐induced graft polymerization

Abstract

Electrochemical DNA (E-DNA) biosensors were fabricated by the physical immobilization of probe DNA, 5 0 -GGA GCT GCT GGC ATT ATT GAA-3 0 , on ionicliquid-multiwalled carbon nanotubes (IL-MWNTs) modified with indium tin oxide (ITO) electrodes to detect Salmonella typhi (S. typhi). IL-MWNTs were prepared by the introduction of 1-butylimidazole bromide onto an epoxy group on poly(GMA)-grafted MWNTs, which were synthesized by radiation-induced graft polymerization of glycidyl methacrylate (GMA) onto MWNTs in aqueous solution. Subsequently, IL-MWNTs were coated onto the ITO electrode surface, and then the physical immobilization of the probe DNA performed in probe DNA solution at room temperature for 1 h. The IL-MWNTs were characterized by elemental analysis, XPS, and TGA. The electron transfer resistance (R et ) of the E-DNA biosensor was evaluated after hybridization of the probe DNA and target DNA using elec-trochemical impedance spectroscopy. The R et increased after the hybridization of probe DNA and target DNA. The DNA used was complementary DNA: 5 0 -TTC AAT AAT GCC AGC AGC TCC-3 0 , single-base mismatch DNA: 5 0 -TTC AAT AAT GGC AGC AGC TCC-3 0 and three-base mismatch DNA: 5 0 -TTC ATT AAT GGC AGC ACG TCC-3 0 . The dynamic detection range for the sequence-specific DNA of target DNA was from 1.0 Â 10 À13 to 1.0 Â 10 À10 mol L À1 with a regression equation R et (X) ¼ 18.6 C þ 128 and regression coefficient (c) of 0.996. The detection limit was determined to be 3.1 Â 10 À14 mol L À1 . The results demonstrated that the sensitivity of this impedance-based DNA sensor was sufficient for the target DNA sequence detection.

Interfaces Based on Carbon Nanotubes, Ionic Liquids and Polymer Matrices for Sensing and Membrane Separation Applications

“…Probe DNA was then physisorbed onto this surface and its binding to target DNA followed electrochemically [17]. Probe DNA was then physisorbed onto this surface and its binding to target DNA followed electrochemically [17].…”

A highly selective electrochemical sensor for nifedipine based on layer‐by‐layer assembly films from polyaniline and multiwalled carbon nanotube

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Design of a probe based on poly(glycidyl methacrylate‐co‐vinylferrocene)‐coated Pt electrode for electrochemical detection of PTEN gene in PCR amplified samples from prostate tissues

“…The detection of specific DNA squence is a basis to the diagnosis and the treatment of various diseases as well as many applications in genetics, pathology, criminology, pharmacogenetics, and food safety . In molecular diagnostic researches based on the analysis of DNA sequence, a variety of the detection methods such as fluorescent, electrophoresis, electrochemiluminecence, quartz crystal microbalance, electrochemical impedance spectroscopy, voltammetry have been developed. Compared with the other methods, the electrochemical detection of DNA provides an advantage due to high sensitivity, low cost, rapid, portability, and compatibility with micro‐fabrication technology .…”