Electrochemical DNA sensor based on the copolymer of proflavine and Azure B for doxorubicin determination

A DNA sensor has been developed for the determination of doxorubicin by consecutive electropolymerization of an equimolar mixture of Azure B and proflavine and adsorption of native DNA from salmon sperm on a polymer film. Electrochemical investigation showed a difference in the behavior of individual drugs polymerized and their mixture. The use of the copolymer offered some advantages, i.e., a higher roughness of the surface, a wider range of the pH sensitivity of the response, a denser and more robust film, etc. The formation of the polymer film and its redox properties were studied using scanning electron microscopy and electrochemical impedance spectroscopy. For the doxorubicin determination, its solution was mixed with DNA and applied on the polymer surface. After that, charge transfer resistance was assessed in the presence of [Fe(CN)6]3−/4− as the redox probe. Its value regularly grew with the doxorubicin concentration in the range from 0.03 to 10 nM (limit of detection 0.01 nM). The DNA sensor was tested on the doxorubicin preparations and spiked samples mimicking blood serum. The recovery was found to be 98–106%. The DNA sensor developed can find application for the determination of drug residues in blood and for the pharmacokinetics studies. © 2020 by the authors. Licensee MDPI, Basel, Switzerland.Russian Science Foundation, RSF: 17-73-20024Funding: This research was funded by Russian Science Foundation, grant no. 17-73-20024

Biosensor to Ensure Food Security and Environmental Control

© 2016 Elsevier B.V.There is an urgent demand in the development of simple and reliable analytical systems for fast detection of potential hazards related to agriculture and food safety. In addition to toxic individual contaminants (pesticides and heavy metals) and biological threats (pathogens and toxins) considered in previous chapters, the biosensors developed for the estimation of food quality and general toxicity assessment are considered with particular emphasis to the problems of their application for real samples testing. The application of biosensors for the detection of food additives and total toxicity and genotoxicity estimation are reviewed for the past 10 years

Electrochemical dna sensor based on poly(Azure a) obtained from the buffer saturated with chloroform

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 spectros-copy. 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. © 2021 by the authors. Licensee MDPI, Basel, Switzerland.This research was funded by Russian Science Foundation, grant number 17‐73‐20024

Glassy Carbon Electrode Modified with Silver Nanodendrites Implemented in Polylactide-Thiacalix[4]arene Copolymer for the Electrochemical Determination of Tryptophan

© 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim. Glassy carbon electrode (GCE) was modified by new polymeric materials obtained from oligolactides by cross-linking with tetracarboxylated thiacalix[4]arene in cone, partial cone and 1,3-alternate configurations and then silver was deposited by potential cycling in the pores of the polymer film. The modified electrode showed highly sensitive and selective signal toward tryptophan which was irreversibly oxidized on the coating due to Ag + assisted accumulation in the surface layer. The role of macrocycle configuration and conditions for Ag nanodendrites formation are described. Granulation of the polymer films caused by the macrocycles improves both the conditions for silver deposition and tryptophan determination. The electrochemical sensor developed makes it possible to determine from 0.1 to 100μM of tryptophan with the limit of detection down to 0.03μM. No interference with oxidation of other amino acids (phenylalanine, histidine, cysteine and tyrosine) was found. The electrochemical sensor developed was validated in the determination of tryptophan sedative medication "Formula of calmness" in the presence of vitamins B 5 and B 6

Electrochemical Determination of Malathion on an Acetylcholinesterase-Modified Glassy Carbon Electrode

© 2017 Taylor & Francis. An acetylcholinesterase biosensor based on glassy carbon electrode modified with carbon black and pillar[5]arene was used for the determination of malathion after its preliminary oxidation. The contributions of enzyme immobilization and oxidation conditions to the improvement of analytical characteristics of the biosensor were considered and quantified. In optimal conditions, the acetylcholinesterase biosensor allows the determination of 40 pM of malathion with 10 min of incubation and 15 pM with 30 min of incubation. The sensitivity of immobilized enzyme was found to be higher than that the free enzyme due to sorbtional accumulation in the modifier layer. Incomplete oxidation of malathion decreased the sensitivity of the assay. The developed acetylcholinesterase biosensor was validated for the determination of malathion residues in grapes, wine, and peanuts. The recoveries calculated against a high-performance liquid chromatography assay were between 80 and 120% due to possible matrix effects and the simplified extraction protocols

Electrochemical DNA sensors and aptasensors based on electropolymerized materials and polyelectrolyte complexes

© 2016 Elsevier B.V.DNA sensors based on oligonucleotides and aptamers immobilized using electropolymerization and layer-by-layer assembling are reviewed. The conditions of electropolymerization and the role of electrosynthesized layers are considered for polyaniline, polypyrrole, polythiophene, polyphenazines and their derivatives with particular attention to immobilization of bioreceptors and signal detection principles. The performance of DNA sensors for hybridization detection and for the determination of low-molecular intercalators and DNA damaging factors is reviewed. Besides, the composition of polyelectrolyte complexes utilizing DNA receptors are considered depending on the analyte nature and functions of polyionic components and auxiliary reagents used for surface layer coatings

Layer-by-layer polyelectrolyte assembles involving DNA as a platform for DNA sensors

The development of DNA-sensors has become significantly important in the past decades due to prospects of application in medicine, biotechnology and exploring fundamental problems related to cell biology and DNA functioning. Layer-by-layer (LbL) immobilization provides unique approach to the implementation of DNA into the surface sensing layers, a crucial step of DNA-sensor development. The review considers main aspects of LbL assembling in DNA-sensor development and application for the detection of complementary oligonucleotides and DNA damage assessment. Besides, electrostatic assembling due to stepwise accumulation of oppositely charged layers, various combinations of covalent binding and affine immobilization are also considered. The characteristics of DNA containing multilayers onto the solid support and the effect of the immobilization techniques and layers assembled on the performance of appropriate DNAsensors are summarized for different target analytes. © 2011 Bentham Science Publishers Ltd

Organic Acid and DNA Sensing with Electrochemical Sensor Based on Carbon Black and Pillar[5]arene

© 2016 WILEY-VCH Verlag GmbH & Co. KGaA, WeinheimElectrochemical sensor has been proposed on the base of glassy carbon electrode (GCE) modified with carbon black (CB) and pillar[5]arene (P[5]A). The characteristics of the peak currents were found to be sensitive to the incubation of the sensor in organic acid and DNA solution. The detection of n×(10−8–10−5) M of organic acid and down to (1–5)×10−18 g of DNA was attributed to the effect of the analytes on the aggregation and relative stability of oxidized and reduced forms of P[5]A. No signal interference with the alkali and alkali-earth metal ions was found. The electrochemical sensor was tested in the detection of specific DNA interactions, i.e. reactive oxygen species damage and intercalating pharmaceuticals detection

Electrochemical DNA sensors and aptasensors based on electropolymerized materials and polyelectrolyte complexes

© 2015 Elsevier B.V. DNA sensors based on oligonucleotides and aptamers immobilized using electropolymerization and layer-by-layer assembling are reviewed. The conditions of electropolymerization and the role of electrosynthesized layers are considered for polyaniline, polypyrrole, polythiophene, polyphenazines and their derivatives with particular attention to immobilization of bioreceptors and signal detection principles. The performance of DNA sensors for hybridization detection and for the determination of low-molecular intercalators and DNA damaging factors is reviewed. Besides, the composition of polyelectrolyte complexes utilizing DNA receptors are considered depending on the analyte nature and functions of polyionic components and auxiliary reagents used for surface layer coatings