scholarly journals Electrochemical DNA Sensor Based on the Copolymer of Proflavine and Azure B for Doxorubicin Determination

Nanomaterials ◽  
2020 ◽  
Vol 10 (5) ◽  
pp. 924
Author(s):  
Anna Porfireva ◽  
Gennady Evtugyn
Keyword(s):  
Polymer Film ◽  
Electrochemical Impedance ◽  
Limit Of Detection ◽  
Polymer Surface ◽  
Charge Transfer Resistance ◽  
Dna Sensor ◽  
Transfer Resistance ◽  
Redox Probe ◽  
Azure B

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.

scholarly journals Impedimetric Determination of Kanamycin in Milk with Aptasensor Based on Carbon Black-Oligolactide Composite

Sensors ◽  
2020 ◽  
Vol 20 (17) ◽  
pp. 4738 ◽  
Author(s):  
Tatiana Kulikova ◽  
Vladimir Gorbatchuk ◽  
Ivan Stoikov ◽  
Alexey Rogov ◽  
Gennady Evtugyn ◽  
...  
Keyword(s):  
Carbon Black ◽  
Electrochemical Impedance ◽  
Limit Of Detection ◽  
3D Structure ◽  
Cationic Polyelectrolyte ◽  
Charge Transfer Resistance ◽  
Transfer Resistance ◽  
Chitosan Matrix ◽  
Negative Effect

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%.

scholarly journals Electrochemical DNA Sensor Based on Poly(Azure A) Obtained from the Buffer Saturated with Chloroform

Sensors ◽  
2021 ◽  
Vol 21 (9) ◽  
pp. 2949
Author(s):  
Anna Porfireva ◽  
Kseniya Plastinina ◽  
Vladimir Evtugyn ◽  
Yurii Kuzin ◽  
Gennady Evtugyn
Keyword(s):  
Dna Damage ◽  
Cyclic Voltammetry ◽  
Quartz Crystal ◽  
Electrochemical Impedance ◽  
Polymer Surface ◽  
Charge Transfer Resistance ◽  
Dna Sensor ◽  
Transfer Resistance ◽  
Electrochemical Dna Sensor ◽  
Azure A

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.

scholarly journals Electrochemical Immunosensor for the Quantification of S100B at Clinically Relevant Levels Using a Cysteamine Modified Surface

Sensors ◽  
2021 ◽  
Vol 21 (6) ◽  
pp. 1929
Author(s):  
Alexander Rodríguez ◽  
Francisco Burgos-Flórez ◽  
José D. Posada ◽  
Eliana Cervera ◽  
Valtencir Zucolotto ◽  
...  
Keyword(s):  
Frequency Analysis ◽  
Surface Characterization ◽  
Electrochemical Impedance ◽  
Limit Of Detection ◽  
Neuronal Damage ◽  
Charge Transfer Resistance ◽  
Single Frequency ◽  
Response Analysis ◽  
Transfer Resistance ◽  
Therapeutic Decisions

Neuronal damage secondary to traumatic brain injury (TBI) is a rapidly evolving condition, which requires therapeutic decisions based on the timely identification of clinical deterioration. Changes in S100B biomarker levels are associated with TBI severity and patient outcome. The S100B quantification is often difficult since standard immunoassays are time-consuming, costly, and require extensive expertise. A zero-length cross-linking approach on a cysteamine self-assembled monolayer (SAM) was performed to immobilize anti-S100B monoclonal antibodies onto both planar (AuEs) and interdigitated (AuIDEs) gold electrodes via carbonyl-bond. Surface characterization was performed by atomic force microscopy (AFM) and specular-reflectance FTIR for each functionalization step. Biosensor response was studied using the change in charge-transfer resistance (Rct) from electrochemical impedance spectroscopy (EIS) in potassium ferrocyanide, with [S100B] ranging 10–1000 pg/mL. A single-frequency analysis for capacitances was also performed in AuIDEs. Full factorial designs were applied to assess biosensor sensitivity, specificity, and limit-of-detection (LOD). Higher Rct values were found with increased S100B concentration in both platforms. LODs were 18 pg/mL(AuES) and 6 pg/mL(AuIDEs). AuIDEs provide a simpler manufacturing protocol, with reduced fabrication time and possibly costs, simpler electrochemical response analysis, and could be used for single-frequency analysis for monitoring capacitance changes related to S100B levels.

scholarly journals Electrochemical properties and thermal stability of epoxy coatings electrodeposited on aluminium and modified aluminium surfaces

2001 ◽  
Vol 66 (11-12) ◽  
pp. 871-880 ◽  
Author(s):  
Vesna Miskovic-Stankovic ◽  
Zorica Lazarevic ◽  
Zorica Kacarevic-Popovic
Keyword(s):  
Thermal Stability ◽  
Electrochemical Impedance ◽  
Corrosion Behaviour ◽  
Charge Transfer Resistance ◽  
Epoxy Coatings ◽  
Transfer Resistance ◽  
Protective Properties ◽  
Chemically Modified ◽  
Thermal Stability Of

The corrosion behaviour of epoxy coatings electrodeposited on aluminium, as well as on electrochemically and chemically modified aluminium were investigated during exposure to 3 % NaCl. Electrochemical impedance spectroscopy (EIS) and thermogravimetric analysis (TGA) were used for the determination of the protective properties of epoxy coatings on aluminium, anodized aluminium, phosphatized and chromatized-phosphatized aluminium. The protective properties of epoxy coatings on anodized and chromatized-phosphatized aluminium are significantly improved with respect to the same epoxy coatings on aluminium and phosphatized aluminium: higher values of the pore resitance and charge-transfer resistance, lower values of the coating capacitance, double-layer capacitance and relative permittivity (from EIS) smaller amount of absorbed water inside the coating (From TGA). On the other hand, the lower values of the ipdt temperature indicate a lower thermal stability of the epoxy coatings on anodized and chromatized-phosphatized aluminium.

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

Chemosensors ◽  
2022 ◽  
Vol 10 (1) ◽  
pp. 33
Author(s):  
Anastasia Goida ◽  
Yurii Kuzin ◽  
Vladimir Evtugyn ◽  
Anna Porfireva ◽  
Gennady Evtugyn ◽  
...  
Keyword(s):  
Methylene Blue ◽  
Electrochemical Impedance ◽  
Limit Of Detection ◽  
Biological Fluids ◽  
Dna Interaction ◽  
Electrochemical Sensing ◽  
Dna Sensor ◽  
Azure B ◽  
Fish Sperm ◽  
Highly Sensitive

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.

scholarly journals Electrochemical DNA Sensors with Layered Polyaniline—DNA Coating for Detection of Specific DNA Interactions

Sensors ◽  
2019 ◽  
Vol 19 (3) ◽  
pp. 469 ◽  
Author(s):  
Tatjana Kulikova ◽  
Anna Porfireva ◽  
Gennady Evtugyn ◽  
Tibor Hianik
Keyword(s):  
Surface Layer ◽  
Electrochemical Impedance ◽  
Charge Transfer Resistance ◽  
Dna Intercalation ◽  
Dna Sensor ◽  
Transfer Resistance ◽  
Atomic Force ◽  
Dna Binding Sites ◽  
Blue Solution ◽  
Artificial Urine

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.

scholarly journals Developing Activated Carbon Veil Electrode for Sensing Salivary Uric Acid

Biosensors ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 287
Author(s):  
Maria A. Bukharinova ◽  
Natalia Yu. Stozhko ◽  
Elizaveta A. Novakovskaya ◽  
Ekaterina I. Khamzina ◽  
Aleksey V. Tarasov ◽  
...  
Keyword(s):  
Uric Acid ◽  
Electrochemical Impedance ◽  
Linear Sweep Voltammetry ◽  
Cost Effective ◽  
Human Saliva ◽  
Charge Transfer Resistance ◽  
Oxidation Potential ◽  
Transfer Resistance ◽  
Highly Sensitive

The paper describes the development of a carbon veil-based electrode (CVE) for determining uric acid (UA) in saliva. The electrode was manufactured by lamination technology, electrochemically activated and used as a highly sensitive voltammetric sensor (CVEact). Potentiostatic polarization of the electrode at 2.0 V in H2SO4 solution resulted in a higher number of oxygen and nitrogen-containing groups on the electrode surface; lower charge transfer resistance; a 1.5 times increase in the effective surface area and a decrease in the UA oxidation potential by over 0.4 V, compared with the non-activated CVE, which was confirmed by energy dispersive X-ray spectroscopy, electrochemical impedance spectroscopy, chronoamperometry and linear sweep voltammetry. The developed sensor is characterized by a low detection limit of 0.05 µM and a wide linear range (0.09–700 µM). The results suggest that the sensor has perspective applications for quick determination of UA in artificial and human saliva. RSD does not exceed 3.9%, and recovery is 96–105%. UA makes a significant contribution to the antioxidant activity (AOA) of saliva (≈60%). In addition to its high analytical characteristics, the important advantages of the proposed CVEact are the simple, scalable, and cost-effective manufacturing technology and the absence of additional complex and time-consuming modification operations.

Quantitative Determination of Triiodothyronine by Electrochemical Impedance Spectroscopic Biosensor Using Gold Nanoparticle-Modified Electrode

2020 ◽  
Vol 20 (11) ◽  
pp. 7163-7168
Author(s):  
Huynh Vu Nguyen ◽  
Anna Go ◽  
Min-Ho Lee
Keyword(s):  
Quantitative Determination ◽  
Gold Nanoparticle ◽  
Modified Electrode ◽  
Electrochemical Impedance ◽  
Low Cost ◽  
Charge Transfer Resistance ◽  
Impedance Change ◽  
Label Free ◽  
Transfer Resistance

A label-free electrochemical impedimetric immunosensor for the detection of Triiodothyronine—a thyroid hormone that functions as the biomarker for monitoring for thyroid dysfunction was developed. The gold nanoparticle-modified electrode was employed to achieve the sensitive determination of Triiodothyronine at a low concentration level. The gold nanoparticle layer on the gold electrode was generated by chronoamperometry method and its resulting characteristics were investigated by scanning electron microscopy. Redox probe [Fe(CN)6]3−/4− and electrochemical impedance spec-troscopy was used for both evaluation of the immobilization of anti-Triiodothyronine antibody on the electrode surface and quantitative determination of target Triiodothyronine in different concentrations. The electrode with absorbed antibodies showed significant changes in charge transfer resistance upon binding the antigen, which resulted in an increase in normalized impedance change as the addition of antigen concentrations over a dynamic linear range of 0.01–100 ng/ml. These results indicated that the proposed immunosensor could be a potential alternative method for determination of Triiodothyronine in clinics with the advantage of low cost and less time-consuming.

scholarly journals NaOH Pretreated Molybdate-Carbon Paste Electrode for the Determination of Phosphate in Seawater by Square Wave Voltammetry with Impedimetric Evaluation

2021 ◽  
Author(s):  
Mahmoud Fatehy Abdalqader Altahan ◽  
Eric Achterberg ◽  
Asmaa Galal ◽  
Magdi Abdel Azzem
Keyword(s):  
Cyclic Voltammetry ◽  
Carbon Paste Electrode ◽  
Electrochemical Impedance ◽  
Limit Of Detection ◽  
Calibration Plot ◽  
Good Precision ◽  
Carbon Paste ◽  
Transfer Resistance ◽  
Paste Electrode

Abstract Here we describe a new electrochemical sensor for PO4 3− detection in seawater. In this work, we prepared a carbon paste electrode (CPE) modified with molybdate and pretreated in 0.1 M NaOH using cyclic voltammetry (CV). The modified CPE was employed for the determination of PO4 3− in artificial seawater (35 g/L NaCl) acidified with sulfuric acid to pH 0.8. An additional cleaning step (cyclic voltammetry (CV)) of 10 cycles in 0.1 M NaOH at −0.5 to 0.5 V was required between PO4 3− determinations to dissolve the phosphomolybdic complex formed on the surface of the working electrode. Electrochemical impedance spectroscopy (EIS) results confirmed that the molybdate-modified CPE (molybdate/CPE) exhibited a low charge-transfer resistance (Rct) toward PO4 3−, and showed an improved analytical performance for different concentrations of PO4 3−. A calibration plot in the range of 0.01–5 µM with a limit of detection (LOD) of 0.003 µM was obtained. The proposed electrode demonstrated good precision (4.3% and 5.8%) for concentrations of 5 and 0.2 µM, respectively. The proposed method was employed to analyze PO4 3− in seawater samples on a research cruise in the North Sea, with results in close agreement to those obtained using conventional colorimetric measuremen

scholarly journals The Experimental Verification of a Generalized Model of Equivalent Circuits

2021 ◽  
Vol 49 (1) ◽  
pp. 1-8
Author(s):  
Zoltán Lukács ◽  
Dávid Baccilieri ◽  
Tamás Kristóf
Keyword(s):  
Charge Transfer ◽  
Electrochemical Impedance ◽  
Charge Transfer Resistance ◽  
Mathematical Treatment ◽  
Frequency Range ◽  
Transfer Resistance ◽  
Generalized Model ◽  
Fitting In ◽  
Adsorption Desorption

The determination of typical parameters of electrochemical systems, e.g. the polarization or charge transfer resistances, can be critical with regard to the application of Electrochemical Impedance Spectroscopy (EIS) if the lower frequency range is biased as a result of transport and/or adsorption/desorption processes. In such cases, the charge transfer resistance should be assessed from the higher frequency range which is typically inadequate in itself as an input for nonlinear parameter fitting. In earlier publications, an alternative mathematical treatment of both the Equivalent Circuit (EC) and of the parameter dispersion was provided using a generalized model of ECs and also a dispersion-invariant model of the electrochemical interface. In the present work, the previously presented experimental EIS results were crosschecked to verify the performance of the generalized model against a series of redox and corrosion systems. The results proved that the applied method is consistent and provides a fairly good correlation between the principal resistance data assessed by different methods.

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