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

Electrochemical DNA Sensor for Valrubicin Detection Based on Poly(Azure C) Films Deposited from Deep Eutectic Solvent

A novel electrochemical DNA sensor was developed for the detection of the anthracycline drug, valrubicin, on the base of poly(Azure C) electropolymerized from the deep eutectic solvent reline and covered with adsorbed DNA from calf thymus. Biosensor assembling was performed by multiple scanning of the potential in one drop (100 µL) of the dye dissolved in reline and placed on the surface of a screen-printed carbon electrode. Stabilization of the coating was achieved by its polarization in the phosphate buffer. The electrochemical characteristics of the electron transfer were determined and compared with a similar coating obtained from phosphate buffer. The use of deep eutectic solvent made it possible to increase the monomer concentration and avoid using organic solvents on the stage of electrode modification. After the contact of the DNA sensor with valrubicin, two signals related to the intrinsic redox activity of the coating and the drug redox conversion were found on voltammogram. Their synchronous changes with the analyte concentration increased the reliability of the detection. In the square-wave mode, the DNA sensor made it possible to determine from 3 µM to 1 mM (limit of detection, 1 µM) in optimal conditions. The DNA sensor was successfully tested in the voltammetric determination of valrubicin in spiked artificial urine, Ringer-Locke solution mimicking plasma electrolytes and biological samples (urine and saliva) with a recovery of 90–110%. After further testing on clinical samples, it can find application in the pharmacokinetics studies and screening of new drugs’ interaction with DNA. © 2023 by the authors.Russian Science Foundation, RSF: 23-13-00163This research was funded by the Russian Science Foundation (grant No. 23-13-00163), https://www.rscf.ru/en/project/23-13-00163 (assessed on 17 August 2023)

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 Sensing of Idarubicin—DNA Interaction Using Electropolymerized Azure B and Methylene Blue Mediation

A highly sensitive electrochemical DNA sensor for detection of the chemotherapeutic drug idarubicin mediated by Methylene blue (MB) has been developed. DNA from fish sperm has been immobilized at the electropolymerized layers of Azure B. The incorporation of MB into the DNA layers substantially increased the sensor sensitivity. The concentration range for idarubicin determination by cyclic voltammetry was from 1 fM to 0.1 nM, with a limit of detection (LOD) of 0.3 fM. Electrochemical impedance spectroscopy (EIS) in the presence of a redox probe ([Fe(CN)6 ]3−/4− ) allowed for the widening of a linear range of idarubicin detection from 1 fM to 100 nM, retaining LOD 0.3 fM. The DNA sensor has been tested in various real and artificial biological fluids with good recovery ranging between 90–110%. The sensor has been successfully used for impedimetric idarubicin detection in medical preparation Zavedos® . The developed DNA biosensor could be useful for the control of the level of idarubicin during cancer therapy as well as for pharmacokinetics studies. © 2022 by the authors. Licensee MDPI, Basel, Switzerland.Funding: A.P. announces the financial support of Russian Science Foundation (grant 17-73-20024). T.H. is grateful to Science Agency VEGA, project No. 1/0419/20, for financial support

Electrochemical DNA sensors based on spatially distributed redox mediators: Challenges and promises

© 2017 IUPAC & De Gruyter. DNA and aptasensors are widely used for fast and reliable detection of disease biomarkers, pharmaceuticals, toxins, metabolites and other species necessary for biomedical diagnostics. In the overview, the concept of spatially distributed redox mediators is considered with particular emphasis to the signal generation and biospecific layer assembling. The application of non-conductive polymers bearing redox labels, supramolecular carriers with attached DNA aptamers and redox active dyes and E-sensor concept are considered as examples of the approach announced

Electrochemical DNA sensors based on electropolymerized materials

The use of electropolymerized materials in the DNA sensors is reviewed with particular emphasis on their functions and specific interactions with DNA and oligonucleotides. Polyaniline, pollypyrrole, polythiophenes and polymeric forms of phenazines play significant role in the immobilization and signal transduction of DNA sensors for the detection of hybridization events, DNA-protein and other specific interactions on the sensor surface. The mechanism of electropolymerization and the influence of oligonucleotides are also considered for various types of polymers. The DNA sensor performance is classified in accordance with the biological targets and composition of the surface layer. © 2012 Elsevier B.V. All rights reserved

Impedimetric determination of kanamycin in milk with aptasensor based on carbon black‐oligolactide composite

The determination of antibiotics in food is important due to their negative effect on human health related to antimicrobial resistance problem, renal toxicity, and allergic effects. We propose an impedimetric aptasensor for the determination of kanamycin A (KANA), which was assembled on the glassy carbon electrode by the deposition of carbon black in a chitosan matrix followed by carbodiimide binding of aminated aptamer mixed with oligolactide derivative of thiacalix[4]arene in a cone configuration. The assembling was monitored by cyclic voltammetry, electrochemical impedance spectroscopy, and scanning electron microscopy. In the presence of the KANA, the charge transfer resistance of the inner interface surprisingly decreased with the analyte concentration within 0.7 and 50 nM (limit of detection 0.3 nM). This was attributed to the partial shielding of the negative charge of the aptamer and of its support, a highly porous 3D structure of the surface layer caused by a macrocyclic core of the carrier. The use of electrostatic assembling in the presence of cationic polyelectrolyte decreased tenfold the detectable concentration of KANA. The aptasensor was successfully tested in the determination of KANA in spiked milk and yogurt with recoveries within 95% and 115%. © 2020 by the authors. Licensee MDPI, Basel, Switzerland.Russian Science Foundation, RSF: 16‐13‐000051/0419/20Funding: I.S. acknowledges financial support from the Russian Science Foundation (grant no. 16‐13‐00005) in the synthesis and application in the biosensor platform of the oligolactides bearing thiacalix[4]arene fragments. T.H. acknowledges funding from the European Union’s Horizon 2020 Research and Innovation Program underthe Marie Sklodowska‐Curie grant agreement no. 690898 and from the Science Grant Agency VEGA, project No.1/0419/20

Polyphenothiazine modified electrochemical aptasensor for detection of human α-thrombin

QCM aptasensor for detection human thrombin has been developed on the base of polymeric forms of phenothiazine dyes, Methylene Blue and Methylene Green. Electrostatic accumulation of the analyte in the polyphenothiazine layer made it possible to increase the sensitivity of QCM detection of thrombin in comparison with bare gold electrodes coated with avidin or neutravidin. The influence of nonspecific binding of human serum albumin and the optimal composition of the surface layers were determined. The aptasensors developed make it possible to detect 10-100 nM of thrombin. © 2007 Wiley-VCH Verlag GmbH & Co. KGaA