Electrochemical DNA Sensors with Layered Polyaniline-DNA Coating for Detection of Specific DNA Interactions.

Tatjana Kulikova,Anna Porfireva,Gennady Evtugyn,Tibor Hianik

doi:10.3390/s19030469

Tatjana Kulikova, Anna Porfireva + Show 2 more

Open Access

https://doi.org/10.3390/s19030469

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Abstract

A DNA sensor has been proposed on the platform of glassy carbon electrode modified with native DNA implemented between two electropolymerized layers of polyaniline. The surface layer was assembled by consecutive stages of potentiodynamic electrolysis, DNA drop casting, and second electrolysis, which was required for capsulation of the DNA molecules and prevented their leaching into the solution. Surface layer assembling was controlled by cyclic voltammetry, electrochemical impedance spectroscopy, atomic force, and scanning electron microscopy. For doxorubicin measurement, the DNA sensor was first incubated in the Methylene blue solution that amplified signal due to DNA intercalation and competition with the doxorubicin molecules for the DNA binding sites. The charge transfer resistance of the inner layer interface decreased with the doxorubicin concentration in the range from 1.0 pM to 0.1 μM (LOD 0.6 pM). The DNA sensor was tested for the analysis of spiked artificial urine samples and showed satisfactory recovery in concentration range of 0.05–10 μM. The DNA sensor developed can find application in testing of antitumor drugs and some other DNA damaging factors.

Highlights

DNA sensors are widely used for the determination of specific biochemical interactions important in medical diagnostics, food quality assessment, and pharmaceutics [1]
We suggest to prepare layered coatings of biosensor with DNA entrapped between two independent PANI
Changes in the charge separation and partial compensation of negative charge of phosphate residues of DNA helix affect the amounts of emeraldine salt responsible for electrochemical signal measured by cyclic voltammetry or electrochemical impedance spectroscopy (EIS)

Summary

Introduction

DNA sensors are widely used for the determination of specific biochemical interactions important in medical diagnostics, food quality assessment, and pharmaceutics [1]. Cytostatic drugs prevent DNA transcription in cancer cells due to DNA intercalation [4] In such in vivo reactions, geometry, specific volume, flexibility, and other properties of DNA molecules are changed. Intercalators can promote oxidative DNA damage via oxidation of guanine residues and formation of 8-oxoguanine, an indicator of oxidative stress [6,7]. For this reason, DNA sensors based on native DNA molecules are considered to be promising for detection of drug residues in biological liquids and for searching more effective and less toxic cytostatic drugs

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