Enzyme-catalyzed signal amplification for electrochemical DNA detection with a PNA-modified electrode

Abstract

The signal amplification technique of peptide nucleic acid (PNA)-based electrochemical DNA sensor was developed in a label-free and one-step method utilizing enzymatic catalysis. Electrochemical detection of DNA hybridization on a PNA-modified electrode is based on the change of surface charge caused by the hybridization of negatively charged DNA molecules. The negatively charged mediator, ferrocenedicarboxylic acid, cannot diffuse to the DNA hybridized electrode surface due to the charge repulsion with the hybridized DNA molecule while it can easily approach the neutral PNA-modified electrode surface without the hybridization. By employing glucose oxidase catalysis on this PNA-based electrochemical system, the oxidized mediator could be immediately reduced leading to greatly increased electrochemical signals. Using the enzymatic strategy, we successfully demonstrated its clinical utility by detecting one of the mutation sequences of the breast cancer susceptibility gene BRCA1 at a sample concentration lower than 10(-9) M. Furthermore, a single base-mismatched sample could be also discriminated from a perfectly matched sample.

Sensitive Electrochemical Detection of the Hydroxyl Radical Using Enzyme-catalyzed Redox Cycling

“…5 Signal amplification in amperometry and voltammetry using enzyme-catalyzed redox cycling, in which an analyte is reproduced with the aid of a redox enzyme, has been extensively studied by many researchers. [6][7][8][9][10][11][12] This technique has been applied to sensitive detection in enzyme immunoassay 8,9,11 and enzyme-linked DNA hybridization assay. 10,12 However, it has not been applied to OH radical detection.…”

“…[6][7][8][9][10][11][12] This technique has been applied to sensitive detection in enzyme immunoassay 8,9,11 and enzyme-linked DNA hybridization assay. 10,12 However, it has not been applied to OH radical detection. In this communication, we present our electrochemical detection of the OH radical using an enzyme-catalyzed signal amplification system.…”

Overview of Electrochemical DNA Biosensors: New Approaches to Detect the Expression of Life

“…For instance, alkaline phosphatase (AIP) [124,125], glucose oxidase (GOx) [126] and horseradish peroxidase (HRP) [98,127] have been used for the fabrication of electrochemical sensors. Today, an ideal biosensor is required to be not only miniaturized and cost-effective, but also capable of simultaneous detection of multiple analytes.…”

Electrochemical and Ultraviolet–visible spectroscopic studies on the interaction of deoxyribonucleic acid with vitamin B6

“…6, the same GC electrode without DNA has no voltammetric peaks in this NaOH solution containing vitamin B6. In alkaline solution both DNA and vitamin B 6 are charged negatively [42,[36][37][38], they should have repelled and been far away from each other, but the electro-catalysis of DNA on vitamin B 6 can take place in the alkaline solution. The phenomena confirmed further that DNA interacts with pyridoxol.…”