Abstract
Electropolymerized redox polymers offer broad opportunities in detection of biospecific interactions of DNA. In this work, Azure A was electrochemically polymerized by multiple cycling of the potential in phosphate buffer saturated with chloroform and applied for discrimination of the DNA damage. The influence of organic solvent on electrochemical properties of the coating was quantified and conditions for implementation of DNA in the growing polymer film were assessed using cyclic voltammetry, quartz crystal microbalance, and electrochemical impedance spectroscopy. As shown, both chloroform and DNA affected the morphology of the polymer surface and electropolymerization efficiency. The electrochemical DNA sensor developed made it possible to distinguish native and thermally and chemically damaged DNA by changes in the charge transfer resistance and capacitance.
Highlights
IntroductionThere is an urgent need in the development of simple and reliable analytical devices for the detection of antioxidants, drugs, biomarkers, and toxic species required in medical diagnostics and food safety assessment [1–5]
Label-free biosensors utilize changes in permeability of the sensing layers caused by analyte implementation and measured mostly by electrochemical impedance spectroscopy (EIS) [26,27]
We propose to perform electropolymerization in the presence of chloroform to improve the performance of the DNA sensor and increase sensitivity of the signal toward anthracycline drugs
Summary
There is an urgent need in the development of simple and reliable analytical devices for the detection of antioxidants, drugs, biomarkers, and toxic species required in medical diagnostics and food safety assessment [1–5]. Interaction with analyte molecules affects both parameters due to partial shielding of the charges and/or charge separation in the recognition event For this reason, monitoring of the redox activity of the polymers shows high sensitivity toward specific DNA interactions. It should be noted that application of such modifiers frequently limits the measurement conditions by pH region required for redox signal recording (polyaniline) or by interference with reactive species able to react with electrodes near the redox activity of appropriate polymers (polyphenothiazines). Films polymerized from organic solvents are normally denser than those deposited from aqueous solutions and contain less water and small ions This complicates charge transfer and redox signal generation on the polymer–DNA interface. Low amounts of organic solvent improve electropolymerization conditions due to higher solubility of the monomer while not affecting implementation of DNA molecules in the growing polymer film
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