scholarly journals Electrochemical Resistive DNA Biosensor for the Detection of HPV Type 16

Molecules ◽  
2021 ◽  
Vol 26 (11) ◽  
pp. 3436
Author(s):  
José R. Espinosa ◽  
Marisol Galván ◽  
Arturo S. Quiñones ◽  
Jorge L. Ayala ◽  
Verónica Ávila ◽  
...  
Keyword(s):  
Modified Electrode ◽  
Point Of Care ◽  
Low Cost ◽  
Relaxation Method ◽  
Charge Transfer Resistance ◽  
Dna Biosensor ◽  
Complementary Sequence ◽  
Transfer Resistance ◽  
20 Nm ◽  
Current Relaxation

In this work, a low-cost and rapid electrochemical resistive DNA biosensor based on the current relaxation method is described. A DNA probe, complementary to the specific human papillomavirus type 16 (HPV-16) sequence, was immobilized onto a screen-printed gold electrode. DNA hybridization was detected by applying a potential step of 30 mV to the system, composed of an external capacitor and the modified electrode DNA/gold, for 750 µs and then relaxed back to the OCP, at which point the voltage and current discharging curves are registered for 25 ms. From the discharging curves, the potential and current relaxation were evaluated, and by using Ohm’s law, the charge transfer resistance through the DNA-modified electrode was calculated. The presence of a complementary sequence was detected by the change in resistance when the ssDNA is transformed in dsDNA due to the hybridization event. The target DNA concentration was detected in the range of 5 to 20 nM. The results showed a good fit to the regression equation ΔRtotal(Ω)=2.99 × [DNA]+81.55, and a detection limit of 2.39 nM was obtained. As the sensing approach uses a direct current, the electronic architecture of the biosensor is simple and allows for the separation of faradic and nonfaradaic contributions. The simple electrochemical resistive biosensor reported here is a good candidate for the point-of-care diagnosis of HPV at a low cost and in a short detection time.

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.

Improvement of Ti/RuO2–IrO2 Anode Lifetime and Electrocatalytical Properties by Using an Eco-Friendly Thermal Decomposition Method Using Polyvinyl Alcohol as Solvent

2019 ◽  
Author(s):  
Charlys Bezerra ◽  
Géssica Santos ◽  
Marilia Pupo ◽  
Maria Gomes ◽  
Ronaldo Silva ◽  
...  
Keyword(s):  
Thermal Decomposition ◽  
Polyvinyl Alcohol ◽  
High Efficiency ◽  
Electrochemical Impedance ◽  
Pechini Method ◽  
Low Cost ◽  
Charge Transfer Resistance ◽  
Transfer Resistance ◽  
Calcination Temperatures ◽  
Service Lifetime

<p>Electrochemical oxidation processes are promising solutions for wastewater treatment due to their high efficiency, easy control and versatility. Mixed metal oxides (MMO) anodes are particularly attractive due to their low cost and specific catalytic properties. Here, we propose an innovative thermal decomposition methodology using <a>polyvinyl alcohol (PVA)</a> as a solvent to prepare Ti/RuO<sub>2</sub>–IrO<sub>2</sub> anodes. Comparative anodes were prepared by conventional method employing a polymeric precursor solvent (Pechini method). The calcination temperatures studied were 300, 400 and 500 °C. The physical characterisation of all materials was performed by X-ray diffraction and scanning electron microscopy coupled with energy dispersive spectroscopy, while electrochemical characterisation was done by cyclic voltammetry, accelerated service lifetime and electrochemical impedance spectroscopy. Both RuO<sub>2</sub> and IrO<sub>2</sub> have rutile-type structures for all anodes. Rougher and more compact surfaces are formed for the anodes prepared using PVA. Amongst temperatures studied, 300 °C using PVA as solvent is the most suitable one to produce anodes with expressive increase in voltammetric charge (250%) and accelerated service lifetime (4.3 times longer) besides reducing charge-transfer resistance (8 times lower). Moreover, the electrocatalytic activity of the anodes synthesised with PVA toward the Reactive Blue 21 dye removal in chloride medium (100 % in 30 min) is higher than that prepared by Pechini method (60 min). Additionally, the removal total organic carbon point out improved mineralisation potential of PVA anodes. Finally, this study reports a novel methodology using PVA as solvent to synthesise Ti/RuO<sub>2</sub>–IrO<sub>2</sub> anodes with improved properties that can be further extended to synthesise other MMO compositions.</p>

scholarly journals A Low Cost Fe3O4–Activated Biochar Electrode Sensor by Resource Utilization of Excess Sludge for Detecting Tetrabromobisphenol A

Micromachines ◽  
2022 ◽  
Vol 13 (1) ◽  
pp. 115
Author(s):  
Suxing Luo ◽  
Meizhi Yang ◽  
Yuanhui Wu ◽  
Jiang Li ◽  
Jun Qin ◽  
...  
Keyword(s):  
Electrochemical Sensors ◽  
Low Cost ◽  
Active Surface ◽  
Charge Transfer Resistance ◽  
Tetrabromobisphenol A ◽  
Active Surface Area ◽  
Excess Sludge ◽  
Transfer Resistance ◽  
Activated Biochar ◽  
Bet Analysis

Owing to its ubiquity in natural water systems and the high toxicity of its accumulation in the human body, it is essential to develop simple and low-cost electrochemical sensors for the determination of 3,3′,5,5′-tetrabromobisphenol A (TBBPA). In this work, Fe3O4–activated biochar, which is based on excess sludge, was prepared and characterized using scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), Fourier transform infrared spectroscopy (FTIR) and BET analysis to analyze its basic features. Subsequently, it was used to fabricate an electrochemical sensor for the detection of TBBPA. The electrochemical test results revealed that the Fe3O4–activated biochar film exhibited a larger active surface area, a lower charge transfer resistance and a higher accumulation efficiency toward TBBPA. Consequently, the peak current of TBBPA was significantly enhanced on the surface of the Fe3O4–activated biochar. The TBBPA sensing platform developed using the Fe3O4–activated biochar composite film, with relatively a lower detection limit (3.2 nM) and a wider linear range (5–1000 nM), was successfully utilized to determine TBBPA levels in water samples. In summary, the effective application of Fe3O4–activated biochar provided eco-friendly and sustainable materials for the development of a desirable high-sensitivity sensor for TBBPA detection.

scholarly journals Low-Cost and Efficient Nickel Nitroprusside/Graphene Nanohybrid Electrocatalysts as Counter Electrodes for Dye-Sensitized Solar Cells

Materials ◽  
2021 ◽  
Vol 14 (21) ◽  
pp. 6563
Author(s):  
Md. Mahbubur Rahman
Keyword(s):  
Solar Cells ◽  
Low Cost ◽  
Photovoltaic Performance ◽  
Dye Sensitized Solar Cells ◽  
Solution Process ◽  
Charge Transfer Resistance ◽  
Counter Electrodes ◽  
Transfer Resistance ◽  
Dye Sensitized ◽  
Sensitized Solar Cells

Novel nickel nitroprusside (NNP) nanoparticles with incorporated graphene nanoplatelets (NNP/GnP) were used for the first time as a low-cost and effective counter electrode (CE) for dye-sensitized solar cells (DSSCs). NNP was synthesized at a low-temperature (25 °C) solution process with suitable purity and crystallinity with a size range from 5 to 10 nm, as confirmed by different spectroscopic and microscopic analyses. The incorporation of an optimized amount of GnP (0.2 wt%) into the NNP significantly improved the electrocatalytic behavior for the redox reaction of iodide (I-)/tri-iodide (I3-) by decreasing the charge-transfer resistance at the CE/electrolyte interface, lower than the NNP- and GnP-CEs, and comparable to the Pt-CE. The NNP/GnP nanohybrid CE when applied in DSSC exhibited a PCE of 6.13% (under one sun illumination conditions) with the Jsc, Voc, and FF of 14.22 mA/cm2, 0.628 V, and 68.68%, respectively, while the PCE of the reference Pt-CE-based DSSC was 6.37% (Jsc = 14.47 mA/cm2, Voc = 0.635 V, and FF = 69.20%). The low cost of the NNP/GnP hybrid CE with comparable photovoltaic performance to Pt-CE can be potentially exploited as a suitable replacement of Pt-CE in DSSCs.

MoO3/CNTs Loading in Separator for Performance-Improving Current-Collector-Free Lithium Ion Batteries

2020 ◽  
Vol 15 (2) ◽  
pp. 204-211
Author(s):  
Peng Peng ◽  
Jiewei Chen ◽  
Kai Niu ◽  
Zhuohai Liu ◽  
Hao Huang ◽  
...  
Keyword(s):  
Lithium Ion Batteries ◽  
Low Cost ◽  
Specific Capacity ◽  
Lithium Ion ◽  
Current Collector ◽  
Charge Transfer Resistance ◽  
Transfer Resistance ◽  
High Specific Capacity ◽  
Composite Separator ◽  
Novel Strategy

A novel strategy for structural design of current-collector-free lithium ion batteries (LIBs) has been proposed, MoO3/CNTs loading on the single side of a separator by a simple spin-coating method. LIBs with such a MoO3-based composite separator eliminate the need for metal current collectors and exhibit an extra high specific capacity (0.2C, ∼1200 mA h g–1). Faster ion transport and lower charge transfer resistance (Rct) of the composite separator were proved compared with the traditional MoO3-based electrode, which results in the increased special capacity. In addition, the pseudocapacitive effect caused by vacancies and narrow interval in the MoO3/CNTs materials also contributes to the high specific capacity of the batteries. The highly efficient ion and electron transport ability of the composite separator were proved in this study, and such a novel design strategy would be an alternative for low-cost LIBs.

A New Approach for Fabricating Low Cost DSSC by Using Carbon-Ink From Inkjet Printer and Its Improvement Efficiency by Depositing Metal Bridge Between Titanium Dioxide Particles

2014 ◽  
Vol 136 (4) ◽  
Author(s):  
Sahrul Saehana ◽  
Darsikin ◽  
Elfi Yuliza ◽  
Pepen Arifin ◽  
Khairurrijal ◽  
...  
Keyword(s):  
Titanium Dioxide ◽  
Solar Cell ◽  
Counter Electrode ◽  
Spray Deposition ◽  
Low Cost ◽  
Charge Transfer Resistance ◽  
Transfer Resistance ◽  
Dye Sensitized ◽  
Carbon Coated ◽  
Inkjet Printer

We report the fabrication of a dye-sensitized solar cell (DSSC) using low-cost materials (carbon ink from an inkjet printer coated on glass as the counter electrode) and made by a combination of spray deposition and doctor blade methods. We noted that the efficiency of the DSSC with the carbon-coated electrode (1.13%) was comparable to that with a platinum-coated counter electrode (1.16%). We also proposed an equivalent circuit for this solar cell. The value of the charge-transfer resistance was determined both experimentally and analytically, and we found that both approaches produced the same results. Moreover, we improved the efficiency of DSSC based carbon by depositing copper nanoparticle into the space between Titanium Dioxide (TiOv2) nanoparticle using electroplating methods.

scholarly journals DNA Biosensor Based on Double-Layer Discharge for the Detection of HPV Type 16

Sensors ◽  
2019 ◽  
Vol 19 (18) ◽  
pp. 3956 ◽  
Author(s):  
Espinosa ◽  
Galván ◽  
Quiñones ◽  
Ayala ◽  
Durón
Keyword(s):  
Double Layer ◽  
Dna Sequences ◽  
Electrochemical Impedance ◽  
Charge Transfer Resistance ◽  
Dna Biosensor ◽  
Transfer Resistance ◽  
Hpv 16 ◽  
Hpv Dna ◽  
Human Papillomavirus 16 ◽  
Feasible Alternative

DNA electrochemical biosensors represent a feasible alternative for the diagnosis of different pathologies. In this work, the development of an electrochemical method for Human Papillomavirus-16 (HPV-16) sensing is reported based on potential relaxation measurements related to the discharge of a complex double layer of a DNA-modified gold electrode. The method used allows us to propose an equivalent circuit (EC) for a DNA/Au electrode, which was corroborated by electrochemical impedance spectroscopy (EIS) measurement. This model differs from the Randles circuit that is commonly used in double-layer simulations. The change in the potential relaxation and associated charge transfer resistance were used for sensing the DNA hybridization by using the redox pair Fe(CN)64-/Fe(CN)63+ as an electrochemical indicator. In order to determinate only the potential relaxation of the composed double layer, the faradic and double-layer current contributions were separated using a rectifier diode arrangement. A detection limit of 0.38 nM was obtained for the target HPV-16 DNA sequences. The biosensor showed a qualitative discrimination between a single-base mismatched sequence and the fully complementary HPV-16 DNA target. The results indicate that the discharge of the double-layer detection method can be used to develop an HPV DNA biosensor.

Au-Pd Bimetallic Nanoparticle Electrodes for Direct Electroreduction of Hexavalent Chromium Complexes

2016 ◽  
Vol 69 (4) ◽  
pp. 423 ◽  
Author(s):  
Roozbeh Siavash Moakhar ◽  
Mohiedin Bagheri Hariri ◽  
Ajay Kushwaha ◽  
Abolghasem Dolati ◽  
Mohammad Ghorbani ◽  
...  
Keyword(s):  
Indium Tin Oxide ◽  
Electrochemical Impedance ◽  
Low Cost ◽  
Charge Transfer Resistance ◽  
Glass Electrode ◽  
Au Nanoparticle ◽  
Electrochemical Technique ◽  
Transfer Resistance ◽  
Pd Nanoparticle ◽  
Bimetallic Nanoparticle

This paper reports a simple, low-cost, and effective electrochemical technique for sensing and reducing CrVI based on a Au-Pd bimetallic nanoparticle (BNP)-decorated indium tin oxide (ITO) conducting glass electrode. It was observed that the Au-Pd BNP-decorated ITO electrode could significantly boost the electrochemical reduction of CrVI when compared with either Au nanoparticle- or Pd nanoparticle-decorated ITO electrodes. These BNP-decorated electrodes exhibited a wide linear concentration range of 0.001–100 μM, a very low detection limit (signal-to-noise ratio = 3) of 0.3 nM, and a high sensitivity of 1.701 μA μM–1. From electrochemical impedance spectroscopy, it was revealed that this significant improvement was mainly due to the reduction in the charge-transfer resistance, which leads to faster free exchange of the reaction intermediates. The proposed Au-Pd BNP electrode also demonstrated excellent stability, selectivity, repeatability, and reproducibility.

scholarly journals Synthesis and Characterization of Zn–Organic Frameworks Containing Chitosan as a Low-Cost Inhibitor for Sulfuric-Acid-Induced Steel Corrosion: Practical and Computational Exploration

Polymers ◽  
2022 ◽  
Vol 14 (2) ◽  
pp. 228
Author(s):  
Mohamed Gouda ◽  
Mai M. Khalaf ◽  
Kamal Shalabi ◽  
Mohammed A. Al-Omair ◽  
Hany M. Abd El-Lateef
Keyword(s):  
Surface Area ◽  
Steel Substrate ◽  
Low Cost ◽  
Steel Corrosion ◽  
Charge Transfer Resistance ◽  
Bet Surface Area ◽  
Gravimetric Analysis ◽  
Metal Interface ◽  
Transfer Resistance ◽  
Duplex Steel

In this work, a Zn–benzenetricarboxylic acid (Zn@H3BTC) organic framework coated with a dispersed layer of chitosan (CH/Zn@H3BTC) was synthesized using a solvothermal approach. The synthesized CH/Zn@H3BTC was characterized by Fourier transform infrared spectroscopy (FTIR), field emission scanning electron microscope (FESEM), thermal gravimetric analysis (TGA), and Brunauer, Emmett, and Teller (BET) surface area. The microscopic observation and the analysis of the BET surface area of CH/Zn@H3BTC nanocomposites indicated that chitosan plays an important role in controlling the surface morphology and surface properties of the Zn@H3BTC. The obtained findings showed that the surface area and particle size diameter were in the range of 80 m2 g−1 and 800 nm, respectively. The corrosion protection characteristics of the CH/Zn@H3BTC composite in comparison to pristine chitosan on duplex steel in 2.0 M H2SO4 medium determined by electrochemical (E vs. time, PDP, and EIS) approaches exhibited that the entire charge transfer resistance of the chitosan- and CH/Zn@H3BTC-composite-protected films on the duplex steel substrate was comparatively large, at 252.4 and 364.8 Ω cm2 with protection capacities of 94.1% and 97.8%, respectively, in comparison to the unprotected metal surface (Rp = 20.6 Ω cm2), indicating the films efficiently protected the metal from corrosion. After dipping the uninhabited and protected systems, the surface topographies of the duplex steel were inspected by FESEM. We found the adsorption of the CH/Zn@H3BTC composite on the metal interface obeys the model of the Langmuir isotherm. The CH/Zn@H3BTC composite revealed outstanding adsorption on the metal interface as established by MD simulations and DFT calculations. Consequently, we found that the designed CH/Zn@H3BTC composite shows potential as an applicant inhibitor for steel protection.

Improvement of Ti/RuO2–IrO2 Anode Lifetime and Electrocatalytical Properties by Using an Eco-Friendly Thermal Decomposition Method Using Polyvinyl Alcohol as Solvent

2019 ◽  
Author(s):  
Charlys Bezerra ◽  
Géssica Santos ◽  
Marilia Pupo ◽  
Maria Gomes ◽  
Ronaldo Silva ◽  
...  
Keyword(s):  
Thermal Decomposition ◽  
Polyvinyl Alcohol ◽  
High Efficiency ◽  
Electrochemical Impedance ◽  
Pechini Method ◽  
Low Cost ◽  
Charge Transfer Resistance ◽  
Transfer Resistance ◽  
Calcination Temperatures ◽  
Service Lifetime

<p>Electrochemical oxidation processes are promising solutions for wastewater treatment due to their high efficiency, easy control and versatility. Mixed metal oxides (MMO) anodes are particularly attractive due to their low cost and specific catalytic properties. Here, we propose an innovative thermal decomposition methodology using <a>polyvinyl alcohol (PVA)</a> as a solvent to prepare Ti/RuO<sub>2</sub>–IrO<sub>2</sub> anodes. Comparative anodes were prepared by conventional method employing a polymeric precursor solvent (Pechini method). The calcination temperatures studied were 300, 400 and 500 °C. The physical characterisation of all materials was performed by X-ray diffraction and scanning electron microscopy coupled with energy dispersive spectroscopy, while electrochemical characterisation was done by cyclic voltammetry, accelerated service lifetime and electrochemical impedance spectroscopy. Both RuO<sub>2</sub> and IrO<sub>2</sub> have rutile-type structures for all anodes. Rougher and more compact surfaces are formed for the anodes prepared using PVA. Amongst temperatures studied, 300 °C using PVA as solvent is the most suitable one to produce anodes with expressive increase in voltammetric charge (250%) and accelerated service lifetime (4.3 times longer) besides reducing charge-transfer resistance (8 times lower). Moreover, the electrocatalytic activity of the anodes synthesised with PVA toward the Reactive Blue 21 dye removal in chloride medium (100 % in 30 min) is higher than that prepared by Pechini method (60 min). Additionally, the removal total organic carbon point out improved mineralisation potential of PVA anodes. Finally, this study reports a novel methodology using PVA as solvent to synthesise Ti/RuO<sub>2</sub>–IrO<sub>2</sub> anodes with improved properties that can be further extended to synthesise other MMO compositions.</p>

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