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 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 aptasensors based on carbon nanotubes - poly(methylene blue) composite

The effect of aptamer structure and immobilization platform on the efficiency of thrombin binding and its detection using electrochemical impedance spectroscopy (EIS) characteristics was investigated with aptasensors based on glassy carbon electrodes covered with multiwalled carbon nanotubes (MWNTs). Aptamers with one or two binding sequences GGTTGGTGTGGTTGG specific for thrombin and poly(dA) and poly(dT) tags able to form dimeric products (aptabodies) were used to establish significance of steric and electrostatic factors in aptasensor performance. We have shown that electropolymerization of methylene blue onto MWNTs significantly improved electrochemical characteristics and sensitivity of thrombin detection against bare MWNTs. Charge transfer resistance and capacitance of the surface layer were measured in the presence of redox probe [Fe(CN)6]3-/4-. Aptasensors make it possible to detect thrombin in the concentration range 1 nM-1 mμM with the limit of detection of 0.7 nM (monitoring resistance changes) and 0.5 nM (capacitance changes), respectively. © 2010 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim

Electrochemical aptasensors based on hybrid metal-organic frameworks

Metal-organic frameworks (MOFs) offer a unique variety of properties and morphology of the structure that make it possible to extend the performance of existing and design new electrochemical biosensors. High porosity, variable size and morphology, compatibility with common components of electrochemical sensors, and easy combination with bioreceptors make MOFs very attractive for application in the assembly of electrochemical aptasensors. In this review, the progress in the synthesis and application of the MOFs in electrochemical aptasensors are considered with an emphasis on the role of the MOF materials in aptamer immobilization and signal generation. The literature information of the use of MOFs in electrochemical aptasensors is classified in accordance with the nature and role of MOFs and a signal mode. In conclusion, future trends in the application of MOFs in electrochemical aptasensors are briefly discussed. © 2020 by the authors. Licensee MDPI, Basel, Switzerland.A.P. acknowledges support of the Russian Science Foundation (grant No 17-73-20024) in part related to the analysis of the reaction conditions and operation of the MOF aptasensors. T.H. acknowledges funding from the Science Grant Agency VEGA, project No.: 1/0419/20

Electrochemical DNA Sensor Based on Acridine Yellow Adsorbed on Glassy Carbon Electrode

Electrochemical DNA sensors offer unique opportunities for the sensitive detection of specific DNA interactions. In this work, a voltametric DNA sensor is proposed on the base of glassy carbon electrode modified with carbon black, adsorbed acridine yellow and DNA for highly sensitive determination of doxorubicin antitumor drug. The signal recorded by cyclic voltammetry was attributed to irreversible oxidation of the dye. Its value was altered by aggregation of the hydrophobic dye molecules on the carbon black particles. DNA molecules promote disaggregation of the dye and increased the signal. This effect was partially suppressed by doxorubicin compensate for the charge of DNA in the intercalation. Sensitivity of the signal toward DNA and doxorubicin was additionally increased by treatment of the layer with dimethylformamide. In optimal conditions, the linear range of doxorubicin concentrations determined was 0.1 pM–1.0 nM, and the detection limit was 0.07 pM. No influence of sulfonamide medicines and plasma electrolytes on the doxorubicin determination was shown. The DNA sensor was tested on two medications (doxorubicin-TEVA and doxorubicin-LANS) and showed recoveries of 102–105%. The DNA sensor developed can find applications in the determination of drug residues in blood and for the pharmacokinetics studies. © 2021 by the authors. Licensee MDPI, Basel, Switzerland.This research was funded by the Russian Science Foundation (A.P., grant no. 17-73-20024, investigations of DNA adsorption DMF influence and DNA-doxorubicin interactions) and the Russian Foundation for Basic Research (G.E., grant no. 20-03-00207, investigation of the AY electrochemical properties and its transfer on the electrode interface)

Polyelectrolyte-mediated assembly of multiwalled carbon nanotubes on living yeast cells.

Here we report the three-dimensional assembly of carbon nanotubes on the polyelectrolyte-coated living Saccharomyces cerevisiae cells using the polyelectrolyte-mediated layer-by-layer approach. Synthetic polyelectrolytes poly(allylamine hydrochloride) and poly(sodium 4-styrenesulfonate) were layer-by-layer deposited on the surfaces of the yeast cells followed by the deposition of water-soluble oxidized multiwalled carbon nanotubes (MWNTs) and an additional outermost polyelectrolyte bilayer. This resulted in the fabrication of polyelectrolyte/nanotubes composite coatings on the cell walls of the yeast cells, which could be clearly seen using the conventional optical microscopy. Transmission and scanning electron microscopy was applied to further investigate the composite coatings. Viability of the encapsulated cells was confirmed using the intercellular esterase activity test. Finally, electrochemical studies using voltammetry and electrochemical impedance measurements were performed, indicating that the composite polyelectrolytes/MWNTs coatings sufficiently affect the electron mediation between the encapsulated yeast cells and the artificial electron acceptor, making it possible to distinguish between living and dead cells. The technique described here may find potential application in the development of microelectronic devices, core-shell and hollow composite microparticles, and electrochemical cell-based biosensors

Electrochemical Biosensors Based on Native DNA and Nanosized Mediator for the Detection of Anthracycline Preparations

© 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim. A novel electrochemical DNA-sensor based on glassy carbon electrode (GCE) modified with electropolymerized Neutral red (NR) and polycarboxylated thiacax[4]arene with covalently attached mediator and electrostatically adsorbed DNA was developed for sensitive detection of anthracycline preparations. Intercalation of doxorubicin, daunorubicin and idarubicin into DNA increases the charge transfer resistance and decreases the electron exchange resulted in decay of the cathodic peak of NR reduction. The DNA-sensor developed makes it possible to determine down to 0.05nM doxorubicin, o.1nM doxorubicin and 0.5nM idarubicin. The DNA-sensor was tested on detection of doxorubicin in pharmaceuticals and artificial blood plasma with 95-100% recovery

Voltammetric Sensor with Replaceable Polyaniline-DNA Layer for Doxorubicin Determination

© 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim New voltammetric DNA sensor has been developed on the base of glassy carbon electrode covered with electropolymerized polyaniline with entrapped native DNA saturated with Methylene blue. The thickness and redox properties of the coating are easily regulated by the number of potential cycles and pH of the solution. Doxorubicin competes with Methylene blue for DNA binding sites and suppresses the electron transfer within the layer. The measurement of the decay of the cathodic peak current made it possible to determine down to 0.01 nM doxorubicin. After that, DNA can be replaced by consecutive treatment of the biosensor with concentrated HCl and fresh DNA solution. Second involvement of DNA was confirmed by electrochemical impedance spectroscopy. The DNA sensor developed was tested on artificial samples mimicking ionic content of human serum and on commercial drug formulation containing doxorubicin

Electrochemical DNA sensors based on nanostructured organic dyes/DNA/polyelectrolyte complexes

© 2014 American Scientific Publishers All rights reserved. Polyelectrolyte complexes based on electropolymerized phenothiazine dyes (Methylene Blue and Methylene Green), poly(allylamine hydrochloride), polystyrene sulfonate and native DNA from salmon sperm have been for the first time obtained by self-assembling on the glassy carbon electrode using the layer-by-layer assembly and characterized using direct current voltammetry and electrochemical impedance spectroscopy. The changes in the charge transfer resistance and capacitance are attributed to the charge separation and the regularity of the layers depending on the number of layers and the position of DNA within the complex. Fenton reagent increases the resistance of the outer interface of the modifier with the maximal effect for the coatings including polymeric form of Methylene Green based coatings and direct contact of the DNA and polyphenothiazines. Meanwhile the selectivity of the response was found higher for the coatings based on poly(Methylene Blue). The difference in the behavior of the polyelectrolyte complex including different components makes it possible to distinguish the response related to the DNA damage and changes in the redox status of polyphenothiazines. Copyrigh