Abnormal Anionic Porphyrin Sensing Effect for HER2 Gene Related DNA Detection via Impedance Difference between MWCNTs and Single-Stranded DNA or Double-Stranded DNA

Abstract

Human epidermal growth factor receptor 2 (HER2) is a key tumor marker for several common and deadly cancers. It is of great importance to develop efficient detection methods for its over-expression. In this work, an electrochemical impedance spectroscopy (EIS) method adjustable by anionic porphyrin for HER2 gene detection has been proposed, based on the impedance difference between multi-walled carbon nanotubes (MWCNTs) and DNA. The interesting finding herein is that with the addition of anionic porphyrin, i.e., meso-tetra(4-sulfophenyl)-porphyrin (TSPP), the impedance value obtained at a glass carbon electrode (GCE) modified with MWCNTs and a single stranded DNA (ssDNA), the probe DNA that might be assembled tightly onto MWCNTs through π-π stacking interaction, gets a slight decrease; however, the impedance value from a GCE modified with MWCNTs and a double stranded DNA (dsDNA), the hybrid of the probe DNA with a target DNA, which might be assembled loosely onto MWCNTs for the screening effect of phosphate backbones in dsDNA, gets an obvious decrease. The reason may be that on the one hand, being rich in negative sulfonate groups, TSPP will try to push DNA far away from CNTs surface due to its strong electrostatic repulsion towards DNA; on the other hand, rich in planar phenyl or pyrrole rings, TSPP will compete with DNA for the surface of CNTs since it can also be assembled onto CNTs through conjugative interactions. In this way, the “loosely assembled” dsDNA will be repelled by this anionic porphyrin and released off CNTs surface much more than the “tightly assembled” ssDNA, leading to a bigger difference in the impedance value between dsDNA and ssDNA. Thus, through the amplification effect of TSPP on the impedance difference, the perfectly matched target DNA could be easily determined by EIS without any label. Under the optimized experimental conditions, this electrochemical sensor shows an excellent linear response to target DNA in a concentration range of 2.0 × 10−11–2.0 × 10−6 M with a limit of detection (LOD) of 6.34 × 10−11 M (S/N = 3). This abnormally sensitive electrochemical sensing performance resulting from anionic porphyrin for DNA sequences specific to HER2 gene will offer considerable promise for tumor diagnosis and treatment.

Recent advances in biosensor devices for HER-2 cancer biomarker detection

“…2 HER-2 detection DNA probe binds tightly onto a CVT modified electrode via p-p stacking interaction and hybridization with the target DNA probe can be measured by EIS. 42 Fig. 3 This scheme illustrates the principle of surface plasmon resonance (SPR) sensors that can detect refractive index (RI) changes within a detection area (<500 nm) as a change of the resonance angle (RA).…”

“…66 The flattening of porphyrin molecules can decrease the distance between CNTs and porphyrin planes. The HER-2 specific DNA probe linked tightly onto CNT modified electrode via π–π stacking interaction and this hybridization with the target DNA probe can be measured with EIS 42 (Fig. 2).…”

Synergetic Sensing Effect of Sodium Carboxymethyl Cellulose and Bismuth on Cadmium Detection by Differential Pulse Anodic Stripping Voltammetry

“…However, these methods have obvious limitations such as sophisticated instrumentation, long operation times, and high running cost [17]. Comparatively, the electrochemical analysis method seems to be more attractive and practicable due to its remarkable sensitivity, simplicity, and low cost [18]. Among the electrochemical methods, differential pulse anodic stripping voltammetry (DPASV) has been successfully used to detect heavy metal ions, which is usually based on special chemically-modified electrodes [19,20].…”