scholarly journals Electrochemical Evaluation of Ion Substituted-Hydroxyapatite on HeLa Cells Plasma Membrane Potential

2018 ◽  
Author(s):  
Bernard Owusu Asimeng ◽  
Elvis Kwason Tiburu ◽  
Elsie Effah Kuafmann ◽  
Lily Peamka ◽  
Claude Fiifi Hayford ◽  
...  
Keyword(s):  
Hela Cells ◽  
Anodic Peak ◽  
Infrared Spectrometry ◽  
Cancer Proliferation ◽  
Peak Current ◽  
Inhibitory Mechanisms ◽  
Redox Active ◽  
Sudden Rise ◽  
Anodic Peak Current ◽  
Voltage Gated Ion Channels

AbstractThis study reports the electrochemical activities of a novel ion substituted-Hydroxyapatite material in contact with HeLa cells. The work was performed to evaluate the inhibitory effects of various concentrations of the material on the ion transfer mechanisms in HeLa cells. The materials (n=2: HAp1 and HAp3) were prepared at different stirring times fromAchatina achatinasnail shells and phosphate-containing solution. The structure of the materials and the trace elements concentration were evaluated using x-ray diffractometry and infrared spectrometry as well as atomic absorption spectroscopy. Electrochemical studies conducted on the cells, after 30 min of exposure to the materials, demonstrated differential responses as elucidated by cyclic voltammetry. The voltammograms revealed HAp1 to be non-redox whereas HAp3 was redox active. Minimal concentrations of HAp1 showed high anodic peak current when compared to the HeLa cells alone, indicating a hyperpolarization of the cells. The peak current gradually reduced as the concentration of HAp1 was increased, and then a sudden rise suggesting inhibition of the cell action potential. HAp3 showed a wavy pattern of the anodic peak current when the material concentration was varied. Peak currents of 0.92 and 0.57 nA were recorded for HAp1 and HAp3, respectively at the highest concentration of 5μL. The results suggest that different inhibitory mechanisms are at play on the voltage-gated ion channels of the cells, indicating the possibility of using the materials to achieve different cancer proliferation inhibition.

scholarly journals A Cyclic Voltammetric Study of the Redox Reaction of Cu(II) in Presence of Ascorbic Acid in Different pH Media

2013 ◽  
Vol 61 (2) ◽  
pp. 161-166 ◽  
Author(s):  
Farhana Haque ◽  
MS Rahman ◽  
Etmina Ahmed ◽  
PK Bakshi ◽  
AA Shaikh
Keyword(s):  
Ascorbic Acid ◽  
Redox Reaction ◽  
Phosphate Buffer Solution ◽  
Anodic Peak ◽  
Buffer Solution ◽  
Current Increase ◽  
Peak Current ◽  
Scan Rate ◽  
Anodic Peak Current ◽  
Electrochemical Redox

The electrochemical redox behavior of Cu(II), and Cu(II) in presence of ascorbic acid has been investigated at glassy carbon electrode (GCE) in aqueous phosphate buffer solution (PBS) at various pH. In the studied pH range the voltammogram consists of a cathodic and an anodic peak. Cu(II) follows one step two-electron transfer electrochemical redox reaction. The intensities of both cathodic and anodic peak current increase with increasing scan rate that are consistent with Randles-Sevcik equation. The linear behavior of peak current with the square root of scan rate indicates that the electrochemical processes are diffusion controlled. In presence of ascorbic acid both of the cathodic and anodic peak current of Cu(II) is reduced and peak positions are shifted compared to those of Cu(II) alone. These observation suggest that Cu(II) undergoes a strong interaction with ascorbic acid in the studied medium. DOI: http://dx.doi.org/10.3329/dujs.v61i2.17064 Dhaka Univ. J. Sci. 61(2): 161-166, 2013 (July)

Electron transport in clay-modified electrodes: study of electron transfer between electrochemically oxidized tris (2,2′-bipyridyl) iron cations and clay structural iron(II) sites

1992 ◽  
Vol 70 (6) ◽  
pp. 1833-1837 ◽  
Author(s):  
Yan Xiang ◽  
Gilles Villemure
Keyword(s):  
Electron Transfer ◽  
Modified Electrodes ◽  
Quantitative Relation ◽  
Cyclic Voltammograms ◽  
Slow Electron ◽  
Cathodic Current ◽  
Peak Current ◽  
Scan Speed ◽  
Anodic Peak Current ◽  
Structural Iron

The cyclic voltammograms of tris (2,2′-bipyridyl) iron(II) ([Fe(bpy)3]2+) adsorbed in clay-modified electrodes made from a range of different smectites were recorded. In all cases, at low scan speed (1 mV/s), the initial anodic peak current was much larger than the initial cathodic peak current. Partial reduction of the clay structural iron further increased the initial anodic to cathodic current ratio, suggesting that the discrepancy between the charge transferred in the anodic and cathodic scans was due to a slow electron transfer between the clay structural Fe(II) and the oxidized bipyridyl cations. However, no clear quantitative relation was found between the measured FeO contents of the different clays and the observed excess anodic currents. In fact, of all the clays tested only one, montmorillonite SWy-1, contained enough Fe(II) for it to account for all of the excess anodic charge transferred in the initial scan.

A Novel Electrochemical Sensor for the Analysis of Salbutamol in Pork Samples by Using NiFe2O4 Nanoparticles Modified Glassy Carbon Electrode

2013 ◽  
Vol 850-851 ◽  
pp. 1279-1282 ◽  
Author(s):  
Su Xing Luo ◽  
Yuan Hui Wu ◽  
Hua Gou ◽  
Yan Liu
Keyword(s):  
Detection Limit ◽  
Electrochemical Sensor ◽  
Glassy Carbon Electrode ◽  
Glassy Carbon ◽  
Electrochemical Method ◽  
Carbon Electrode ◽  
Modified Glassy Carbon Electrode ◽  
Peak Current ◽  
Anodic Peak Current ◽  
Pork Samples

In this work, a simple and sensitive electrochemical method sensor was developed to determine salbutamol based on magnetic NiFe2O4nanoparticles modified glassy carbon electrode. It was found the anodic peak current of salbutamol was linear with the concentration of salbutamol from 2.0 μM to 60 μM with a detection limit of 1.0 μM (S/N=3). The developed method was successfully applied to determine salbutamol content in pork samples with satisfactory results.

scholarly journals Characterization and Inhibitory Effects of Magnetic Iron Oxide Nanoparticles Synthesized from Plant Extracts on HeLa Cells

2020 ◽  
Vol 2020 ◽  
pp. 1-11
Author(s):  
Bernard Owusu Asimeng ◽  
Emmanuel Nyankson ◽  
Johnson Kwame Efavi ◽  
Amartey Nii Amarkai ◽  
Gloria Pokuaa Manu ◽  
...  
Keyword(s):  
Hela Cells ◽  
Anodic Peak ◽  
Molar Ratio ◽  
Inhibitory Effects ◽  
Magnetic Iron Oxide Nanoparticles ◽  
Maize Leaves ◽  
Crystallite Sizes ◽  
Magnetic Fe3o4 Nanoparticles ◽  
Cell Inhibition

Magnetic Fe3O4 nanoparticles were synthesized from maize leaves and plantain peels extract mediators. Particles were characterized, and the inhibitory effects were studied on HeLa cells in vitro using cyclic voltammetry (CV). Voltammograms from the CV show that Fe3O4 NPs interaction with HeLa cells affected their electrochemical behavior. The nanoparticles formed with higher Fe3+/Fe2+ molar ratio (2.8 : 1) resulted in smaller crystallite sizes compared to those formed with lower Fe3+/Fe2+ molar ratio (1.4 : 1). The particles with the smallest crystallite size showed higher anodic peak currents, whereas the larger crystallite sizes resulted in lower anodic peak currents. The peak currents relate to cell inhibition and are confirmed by the half-maximum inhibitory concentration (IC50). The findings show that the particles have a different inhibitory mechanism on HeLa cells ion transfer and are promising to be further exploited for cancer treatment.

scholarly journals Electrochemical Response of Saccharomyces cerevisiae Corresponds to Cell Viability upon Exposure to Dioclea reflexa Seed Extracts and Antifungal Drugs

Biosensors ◽  
2019 ◽  
Vol 9 (1) ◽  
pp. 45
Author(s):  
Patrick Arthur ◽  
Anthony Yeboah ◽  
Ibrahim Issah ◽  
Srinivasan Balapangu ◽  
Samuel Kwofie ◽  
...  
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Cell Death ◽  
Cell Growth ◽  
Cell Viability ◽  
Bioactive Compounds ◽  
Electrochemical Behavior ◽  
Peak Current ◽  
Water Extracts ◽  
Anodic Peak Current ◽  
Seed Extracts

Dioclea reflexa bioactive compounds have been shown to contain antioxidant properties. The extracts from the same plant are used in traditional medical practices to treat various diseases with impressive outcomes. In this study, ionic mobility in Saccharomyces cerevisiae cells in the presence of D. reflexa seed extracts was monitored using electrochemical detection methods to link cell death to ionic imbalance. Cells treated with ethanol, methanol, and water extracts were studied using cyclic voltammetry and cell counting to correlate electrochemical behavior and cell viability, respectively. The results were compared with cells treated with pore-forming Amphotericin b (Amp b), as well as Fluconazole (Flu) and the antimicrobial drug Rifampicin (Rif). The D. reflexa seed water extract (SWE) revealed higher anodic peak current with 58% cell death. Seed methanol extract (SME) and seed ethanol extract (SEE) recorded 31% and 22% cell death, respectively. Among the three control drugs, Flu revealed the highest cell death of about 64%, whereas Amp b and Rif exhibited cell deaths of 35% and 16%, respectively, after 8 h of cell growth. It was observed that similar to SWE, there was an increase in the anodic peak current in the presence of different concentrations of Amp b, which also correlated with enhanced cell death. It was concluded from this observation that Amp b and SWE might follow similar mechanisms to inhibit cell growth. Thus, the individual bioactive compounds from the water extracts of D. reflexa seeds could further be purified and tested to validate their potential therapeutic application. The strategy to link electrochemical behavior to biochemical responses could be a simple, fast, and robust screening technique for new drug targets and to understand the mechanism of action of such drugs against disease models.

scholarly journals Generation of a Highly Efficient Electrode for Ethanol Oxidation by Simply Electrodepositing Palladium on the Oxygen Plasma-Treated Carbon Fiber Paper

Catalysts ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 248
Author(s):  
Houg-Yuan Pei ◽  
Chen-Han Lin ◽  
Wei Lin ◽  
Chiun-Jye Yuan
Keyword(s):  
Carbon Fiber ◽  
Current Density ◽  
Oxygen Plasma ◽  
Ethanol Oxidation ◽  
Peak Current Density ◽  
Peak Current ◽  
Highly Efficient ◽  
Carbon Fiber Paper ◽  
Anodic Peak Current ◽  
Treated Carbon

In this study, a highly efficient carbon-supported Pd catalyst for the direct ethanol fuel cell was developed by electrodepositing nanostructured Pd on oxygen plasma-treated carbon fiber paper (Pd/pCFP). The oxygen plasma treatment has been shown to effectively remove the surface organic contaminants and add oxygen species onto the CFP to facilitate the deposition of nano-structured Pd on the surface of carbon fibers. Under the optimized and controllable electrodeposition method, nanostructured Pd of ~10 nm can be easily and evenly deposited onto the CFP. The prepared Pd/pCFP electrode exhibited an extraordinarily high electrocatalytic activity towards ethanol oxidation, with a current density of 222.8 mA mg−1 Pd. Interestingly, the electrode also exhibited a high tolerance to poisoning species and long-term stability, with a high ratio of the forward anodic peak current density to the backward anodic peak current density. These results suggest that the Pd/pCFP catalyst may be a promising anodic material for the development of highly efficient direct alcohol fuel cells.

scholarly journals PEDOT:PSS–MODIFIED PLATINUM MICROELECTRODES FOR MEASUREMENTS IN AQUEOUS MEDIA: EFFECT OF POLYMER SURFACE AREA ON LONG-TERM ANODIC PEAK CURRENT STABILITY

2017 ◽  
Vol 18 (2) ◽  
pp. 11-15 ◽  
Author(s):  
Wan Wardatul Amani Wan Salim ◽  
Abdelmohsen Benoudjit ◽  
Habibah Farhana Abdul Guthoos ◽  
Farrah Aida Arris
Keyword(s):  
Surface Area ◽  
Aqueous Media ◽  
Polymer Surface ◽  
Media Effect ◽  
Liquid Media ◽  
Peak Current ◽  
Styrene Sulfonate ◽  
Anodic Peak Current ◽  
Poly Styrene Sulfonate ◽  
Global Threat

Contamination of drinking water by hazardous agents is becoming a serious global threat, so it is necessary to develop more efficient sensing technologies for applications in liquid media. The limited working lifetime of electrochemical biosensors, especially when measurements are made continuously in liquid media, remains an unsolved challenge. We studied the effect of PEDOT:PSS surface area on platinum microelectrodes with respect to electrode ability to conduct reversible ion-to-electron transduction in liquid media. Electropolymerization of 3,4-ethylenedioxythiophene:poly(styrene sulfonate) EDOT:PSS to poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate) (PEDOT:PSS) was conducted on microplatinum electrodes 5 and 10 mm long using a galvanostatic mode. Cyclic voltammetry was used to determine capacitive peak current; higher peak current indicates higher redox capacitance. Field-emisison scanning-electron microscopy was used to study the surface morphology of the PEDOT:PSS transucer layer after measurement in liquid media. The anodic capacitive peak currents did not differ significantly between the two electrodes at day one (~0.20 mA); however, peak current decreased by ~ 20% and ~ 80% at day six for 10- and-5 mm electrode lengths, respectively. The results imply that PEDOT:PSS surface area plays a role in transduction of PEDOT:PSS in aqueous media.

Copper Selenocyanate Formation on the Copper Anode.

1997 ◽  
Vol 50 (4) ◽  
pp. 321 ◽  
Author(s):  
Paul A. Kilmartin ◽  
Graham A. Wright
Keyword(s):  
Film Growth ◽  
Raman Band ◽  
Sweep Rate ◽  
Open Circuit ◽  
Anodic Peak ◽  
Copper Anode ◽  
Midpoint Potential ◽  
Anodic Peak Current ◽  
Barrier Film

The formation of CuSeCN on a copper anode was studied in 0·1 and 0·5 mol dm-3 KSeCN solutions. A thin film of polycrystalline CuSeCN was produced with a midpoint potential between the anodic and cathodic peaks for 0·1 mol dm-3 KSeCN at - 0·253 V, close to the open-circuit potential of - 0·249 V. A precursory anodic peak or shoulder was seen at about - 0·210 V, and was ascribed to the formation of a primary (barrier) film. The anodic peak currents for the primary film were linearly dependent upon the sweep rate. Potential steps into the primary film region produced current transients, with the current decaying in proportion to the reciprocal of time. The anodic peak current and potential for the secondary polycrystalline film were proportional to the square root of the sweep rate, an effect which is consistent with a model for porous film growth controlled by the resistance across the underlying barrier film. A weak Raman band due to Se-bonded CuSeCN at 2164 cm-1 was also observed in situ.

scholarly journals La2O3/Co3O4 nanocomposite modified screen printed electrode for voltammetric determination of sertraline

2020 ◽  
Vol 85 (4) ◽  
pp. 505-515
Author(s):  
Sayed Mohammadi ◽  
Hadi Beitollahi ◽  
Tahereh Rohani ◽  
Hossein Allahabadi ◽  
Somayeh Tajik
Keyword(s):  
Limit Of Detection ◽  
Electrochemical Determination ◽  
Current Response ◽  
Screen Printed Electrode ◽  
Peak Current ◽  
Anodic Peak Current ◽  
Pulse Voltammetry ◽  
Significant Increment ◽  
Screen Printed

La2O3/Co3O4 nanocomposite was synthesized and then used for the modification of screen-printed electrode (SPE) prior to the electrochemical determination of sertraline. A significant increment in peak current response was observed and peak potential also shifted towards less positive potentials showing the facilitated oxidation procedure at surface of modified SPE (La2O3/ /Co3O4/SPE). The quantitative determination of sertraline was carried out by using different pulse voltammetry and the anodic peak current was found to increase with increasing sertraline concentration in the linear range of 5.0400.0 ?M with limit of detection as 1.0 ?M. The prepared La2O3/Co3O4/SPE has been successfully used for detecting sertraline in sertraline tablet and urine samples with excellent recoveries.

Electrochemical Properties Test of Vanadium Electrolyte Containing V (III) and V (IV) Ion

2014 ◽  
Vol 809-810 ◽  
pp. 822-830 ◽  
Author(s):  
Wei Zao Liu ◽  
Dong Mei Luo ◽  
Dan Li ◽  
Xiao Ling Meng ◽  
Fan Bo Zeng
Keyword(s):  
Cyclic Voltammetry ◽  
Current Density ◽  
Redox Reaction ◽  
Graphite Electrode ◽  
Electrochemical Activity ◽  
Cathodic Peak ◽  
Peak Current Density ◽  
Vanadium Concentration ◽  
Peak Current ◽  
Anodic Peak Current

The electrochemical behavior of vanadium solution containing V (III) and V (IV) ion each 50% was characterized by cyclic voltammetry and chronopotentiometry with different working electrodes, temperatures, H2SO4concentrations and vanadium ion concentrations. Cyclic voltammetry analysis indicated that V(IV)/V(V) redox reaction at graphite electrode showed good electrochemical activity and reversibility while V(III)/V(II) redox reaction showed bad electrochemical activity and reversibility on Pt, glassy-carbon and graphite electrode. The cathodic peak current density of V(III)/V(II) couples increased first then remained almost unchanged as temperature raised and approached a maximum at 60°C. With H2SO4concentration elevated, the electrolyte became viscous and diffusion step was the controlling step. The electrochemical activity of electrolyte increased with ascending vanadium concentration, so did the reversibility of V(IV)/V(V) couples. However, no matter what vanadium concentration was, the reversibility of V(III)/V(II) couples stayed poor. Stirring in solution benefited to the anodic peak current density of V(IV)/V(V) couples whereas it did not to the cathodic peak current density of V(III)/V(II) couples. The diffusion coefficients of V(III),V(IV) were calculated as 1.17×10-5,0.919×10-5cm2·s-1, respectively. Chronopotentiometry test indicated that solution as anolyte showed good charging performance while solution as catholyte showed poor charging performance.

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