scholarly journals Specific Detection of PE-Included Vesicles Using Cyclic Voltammetry

2021 ◽  
Vol 11 (8) ◽  
pp. 3660
Author(s):  
Yeseul Park ◽  
Jin-Won Park
Keyword(s):  
Cyclic Voltammetry ◽  
Binding Site ◽  
Gold Surface ◽  
Electric Property ◽  
Specific Detection ◽  
Cv Measurements

The binding between cinnamycin and the phosphatidylethanolamine (PE)-included vesicles was monitored using cyclic voltammetry (CV) measurements and interpreted in terms of the composition of the vesicles and the monolayer binding site. The monolayer was composed of pure 11-mercapto-1-undecanol (MUD) to 90% MUD/10% 16-mercaptohexadecanoic acid (MHA) on a gold surface. Cinnamycin was immobilized on each monolayer. The vesicles, prepared at the desired ratio of the phospholipids, were injected on the cinnamycin-immobilized surface. CV experiments were performed for each step. For the pure-dipalmitoylphosphatidyl-choline (DPPC) vesicles on all of monolayers and the DPPC/dipalmitoylphosphatidyl-ethanolamine (DPPE) vesicles on the pure-MUD monolayer, the electric property of the surface was little changed. However, the vesicles made with 90% DPPC/10% DPPE on the monolayer prepared with 99% MUD/1% MHA to 90% MUD/10% MHA showed a consistent decrease in the CV response. Additionally, in the 95% DPPC/5% DPPE vesicles and the 99.5% MUD/0.5% MHA monolayer, variances in the responses were observed.

scholarly journals Suitability of the Cyclic Voltammetry Measurements and DPPH• Spectrophotometric Assay to Determine the Antioxidant Capacity of Food-Grade Oenological Tannins

Molecules ◽  
2019 ◽  
Vol 24 (16) ◽  
pp. 2925 ◽  
Author(s):  
Arianna Ricci ◽  
Giuseppina Paola Parpinello ◽  
Nemanja Teslić ◽  
Paul Andrew Kilmartin ◽  
Andrea Versari
Keyword(s):  
Cyclic Voltammetry ◽  
Colorimetric Assay ◽  
Radical Scavenging ◽  
Calibration Graph ◽  
Spectrophotometric Assay ◽  
Experimental Conditions ◽  
Fast Analysis ◽  
Cv Measurements ◽  
And Control ◽  
Analytical Approaches

Twenty commercially available oenological tannins (including hydrolysable and condensed) were assessed for their antiradical/reducing activity, comparing two analytical approaches: The 2,2-diphenyl-1-picrylhydrazyl (DPPH•) radical scavenging spectrophotometric assay and the cyclic voltammetry (CV) electrochemical method. Electrochemical measurements were performed over a −200 mV–500 mV scan range, and integrated anodic currents to 500 mV were used to build a calibration graph with (+)-catechin as a reference standard (linear range: From 0.0078 to 1 mM, R2 = 0.9887). The CV results were compared with the DPPH• assay (expressed as % of radical scavenged in time), showing high correlation due to the similarity of the chemical mechanisms underlying both methods involving polyphenolic compounds as reductants. Improved correlation was observed by increasing the incubation time with DPPH• to 24 h (R2 = 0.925), demonstrating that the spectrophotometric method requires a long-term incubation to complete the scavenging reaction when high-molecular weight tannins are involved; this constraint has been overcome by using instant CV measurements. We concluded that the CV represents a valid alternative to the DPPH• colorimetric assay, taking advantage of fast analysis and control on the experimental conditions and, because of these properties, it can assist the quality control along the supply chain.

Integrity and redox properties of homogeneous and heterogeneous DNA films on gold surface probed by cyclic voltammetry

2002 ◽  
Vol 413 (1-2) ◽  
pp. 218-223 ◽  
Author(s):  
Hellas C.M Yau ◽  
Hing Leung Chan ◽  
Sen-fang Sui ◽  
Mengsu Yang
Keyword(s):  
Cyclic Voltammetry ◽  
Gold Surface ◽  
Redox Properties ◽  
Dna Films

Design and synthesis of dichromeno[2,3-b;3′,2′-e]pyridine-12,14-dione to evaluate its optical properties

2017 ◽  
Vol 41 (10) ◽  
pp. 3887-3893 ◽  
Author(s):  
Pritam Biswas ◽  
Jaydip Ghosh ◽  
Tapas Sarkar ◽  
Debabrata Jana ◽  
Chandrakanta Bandyopadhyay
Keyword(s):  
Cyclic Voltammetry ◽  
Optical Properties ◽  
Thermogravimetric Analysis ◽  
Dft Calculations ◽  
Design And Synthesis ◽  
Mild Conditions ◽  
Cv Measurements

An unambiguous synthesis of dichromeno[2,3-b;3′,2′-e]pyridine-12,14-diones has been developed under mild conditions and their optical properties have been evaluated by studying UV-vis absorption and photoluminescence (PL) spectroscopy, cyclic voltammetry (CV) measurements, DFT calculations and thermogravimetric analysis.

Electrochromic and Electrochemical Properties of Nickel Oxide Thin Films Prepared by a Modified Sol-Gel Method

2008 ◽  
Vol 47-50 ◽  
pp. 625-629 ◽  
Author(s):  
X.H. Xia ◽  
J.P. Tu ◽  
J. Zhang ◽  
X.L. Wang
Keyword(s):  
Thin Films ◽  
Cyclic Voltammetry ◽  
Sol Gel ◽  
Gel Method ◽  
Sol Gel Method ◽  
Electrochemical Reversibility ◽  
Vis Spectroscopy ◽  
Ito Glass ◽  
Higher Temperature ◽  
Cv Measurements

NiO thin films were prepared on ITO glass by a modified sol-gel method in combination with a following annealing process. The XRD results show that the film annealed at 280 °C is amorphous, while the films annealed at and above 300 °C are cubic NiO phase. The electrochromic performances of the annealed films were characterized by means of UV–vis spectroscopy and cyclic voltammetry (CV) measurements. The film annealed at 280 °C exhibits a noticeable electrochromism with a variation of transmittance up to 76 % at 550 nm. The cyclic voltammetry (CV) measurements reveal that the film annealed at higher temperature has better electrochemical reversibility.

scholarly journals On the stability of platinum-composite electrocatalysts prepared with different substrate materials

2016 ◽  
Vol 6 (1) ◽  
pp. 29
Author(s):  
Milica G. Košević ◽  
Gavrilo M. Šekularac ◽  
Vladimir V. Panić
Keyword(s):  
Cyclic Voltammetry ◽  
Steady State ◽  
Sol Gel ◽  
Colloidal Dispersion ◽  
Sweep Rate ◽  
Initial Activity ◽  
Microwave Assisted ◽  
Commercial Carbon ◽  
The Stability ◽  
Cv Measurements

<p><span lang="EN-US">Cyclic voltammetry (CV) measurements were conducted and analyzed for a preliminary estimation of the stability of composite electrocatalysts based on Pt. The changes in CV currents of platinum nanoparticles supported on TiO<sub>2</sub> were compared to the changes of those supported on commercial carbon. TiO<sub>2</sub> was synthesized by sol-gel method and Pt was deposited from Pt colloidal dispersion synthesized by microwave-assisted polyol process. It was found that Pt component in both Pt/TiO<sub>2</sub> and Pt/C behaves similarly with respect to stability and activity during the cycling. The loss in activity with cycling was linear and strongly depended on sweep rate, i.e., the relative loss is higher at lower sweep rates. The steady state activities for both electrocatalysts were reached at the level of 65 % of initial activity and required more than 100 voltammetric cycles.</span></p>

scholarly journals Optimization of the qPCR temperature profile is essential for efficient and rapid detection of Sars-CoV-2

2021 ◽  
Author(s):  
Pál Salamon ◽  
Emese Bálint ◽  
Gyöngyi Tar ◽  
Beáta Albert
Keyword(s):  
Reaction Time ◽  
Binding Site ◽  
Temperature Profile ◽  
Rapid Detection ◽  
Target Gene ◽  
Target Product ◽  
Detection Time ◽  
Specific Detection ◽  
Total Reaction ◽  
Total Reaction Time

Abstract qPCR protocols should specify shorter annealing and extension times to optimize the efficacy of the target product. These specific times must be long enough for the complexes to form at the correct binding site, but if these times are too long, it can result in unspecified products. Our results show that reducing the reaction time during the second cycle can increase the specificity of the resulting product and thus reduce the total reaction time. The overall temperature profile, optimized for the target gene, shortens the detection time, allowing faster and more specific detection of the presence of the Sars-CoV-2.

scholarly journals Functionalized Palladium Nanoparticles for Hydrogen Peroxide Biosensor

2011 ◽  
Vol 2011 ◽  
pp. 1-4 ◽  
Author(s):  
H. Baccar ◽  
T. Ktari ◽  
A. Abdelghani
Keyword(s):  
Hydrogen Peroxide ◽  
Cyclic Voltammetry ◽  
Detection Limit ◽  
Horseradish Peroxidase ◽  
Palladium Nanoparticles ◽  
Gold Electrode ◽  
Volume Ratio ◽  
Gold Surface ◽  
Amino Groups ◽  
Limit Detection

We present a comparison between two biosensors for hydrogen peroxide (H2O2) detection. The first biosensor was developed by the immobilization of Horseradish Peroxidase (HRP) enzyme on thiol-modified gold electrode. The second biosensor was developed by the immobilization of cysteamine functionalizing palladium nanoparticles on modified gold surface. The amino groups can be activated with glutaraldehyde for horseradish peroxidase immobilization. The detection of hydrogen peroxide was successfully observed in PBS for both biosensors using the cyclic voltammetry and the chronoamperometry techniques. The results show that the limit detection depends on the large surface-to-volume ratio attained with palladium nanoparticles. The second biosensor presents a better detection limit of 7.5 μM in comparison with the first one which is equal to 75 μM.

scholarly journals Self-Assembled Monolayers from Symmetrical Di-Thiols: Preparation, Characterization and Application for the Assembly of Electrochemically Active Films

2021 ◽  
Vol 6 (1) ◽  
pp. 17
Author(s):  
Arwa Laroussi ◽  
Małgorzata Kot ◽  
Jan Ingo Flege ◽  
Noureddine Raouafi ◽  
Vladimir Mirsky
Keyword(s):  
Cyclic Voltammetry ◽  
Photoelectron Spectroscopy ◽  
Surface Concentration ◽  
Gold Surface ◽  
Thiol Group ◽  
Strong Stability ◽  
Terminal Group ◽  
High Concentration ◽  
Electrochemically Active ◽  
Self Assembled

1,3-dimercaptopropan-2-ol, a symmetrical di-thiol, has been synthesized and applied as a new type of anchor molecule to prepare a self-assembled monolayer (SAM) on a gold surface. The formed monolayers were studied by cyclic voltammetry, impedance spectroscopy, X-ray photoelectron spectroscopy, kinetic capacitance, and contact angle measurements. The SAM structure depends on the adsorption conditions. A short incubation time of the electrode at high concentration of this di-thiol leads to the predominating binding through one thiol group of the adsorbate to the gold surface, while a long incubation at low concentration leads to the predominating binding by both thiol groups. A comparative study of the desorption and replacement of SAMs indicates a strong stability increase when the SAM molecules bond gold surfaces by two bonds mainly. This monolayer was used to immobilize electrochemically active p-benzoquinone moiety. The surface concentration of p-benzoquinone obtained from cyclic voltammetry is 2.5 ± 0.2 × 10−10 mol cm−2, which corresponds to the functionalization of 65 ± 5% of SAM molecules. The obtained highly stable SAM with redox-active terminal group can be applied for different tasks of chemical sensing and biosensing. As an example, an application of this system for electrocatalytical oxidation of dihydronicotinamide adenosine dinucleotide (NADH) was tested.

scholarly journals Cyclic voltammetry: a simple method for determining contents of total and free iron ions in sodium ferric gluconate complex

2020 ◽  
Author(s):  
Hong Liu ◽  
Qiao Yu ◽  
Yixuan Ma ◽  
Baoyu Liu ◽  
Hongchun Pan
Keyword(s):  
Cyclic Voltammetry ◽  
Iron Content ◽  
Total Iron ◽  
Iron Ions ◽  
Experimental Conditions ◽  
Simple Method ◽  
Free Iron ◽  
Linear Relationships ◽  
Technological Level ◽  
Cv Measurements

<p class="PaperAbstract">Sodium ferric gluconate complex (SFGC) is the third generation of iron supplement of polysaccharide iron (III) complex (PIC). For evaluation of technological level and application value of the prepared SFGC, it would be of great significance to determine the iron content in SFGC in a simple but effective way. This paper introduces the cyclic voltammetry (CV) method for determination of iron content in SFGC. Under established optimal experimental conditions, the content of free iron ions can be directly scanned and calculated, while the total iron content can also be determined by completely acidifying SFGC into Fe<sup>3+</sup> ions. After optimizing and screening, the optimal scanning conditions are determined as pH 3 and 0.05 V/s of the scanning rate. Prior CV measurements, 0.4 V of the enrichment potential, and 3 min of the enrichment time are found optimal. It has also been verified that CO<sub>3</sub><sup>2-</sup> ions present in the solution show little interference in the system within the experimental range of investigation. The contents of free Fe<sup>3+</sup>, Fe<sup>2+</sup> ions and the total iron determined after acid-hydrolysis of SFGC can be accurately calculated according to the corresponding linear relationships between peak currents and iron concentrations. In this paper, the repeatability and accuracy of the method are verified, and its feasibility as a convenient and effective method to determine the iron supplements is confirmed.</p>

Estimation of the composition of intermetallic compounds in LiCl–KCl molten salt by cyclic voltammetry

2016 ◽  
Vol 190 ◽  
pp. 387-398 ◽  
Author(s):  
Ya L. Liu ◽  
Kui Liu ◽  
Li Y. Yuan ◽  
Zhi F. Chai ◽  
Wei Q. Shi
Keyword(s):  
Cyclic Voltammetry ◽  
Molten Salt ◽  
Intermetallic Compounds ◽  
Reduction Process ◽  
Reduction Processes ◽  
Cv Measurements ◽  
Co Reduction

In this work, the compositions of Ce–Al, Er–Al and La–Bi intermetallic compounds were estimated by the cyclic voltammetry (CV) technique. At first, CV measurements were carried out at different reverse potentials to study the co-reduction processes of Ce–Al, Er–Al and La–Bi systems. The CV curves obtained were then re-plotted with the current as a function of time, and the coulomb number of each peak was calculated. By comparing the coulomb number of the related peaks, the compositions of the Ce–Al, Er–Al and La–Bi intermetallic compounds formed in the co-reduction process could be estimated. The results showed that Al11Ce3, Al3Ce, Al2Ce and AlCe could be formed by the co-reduction of Ce(iii) and Al(iii). For the co-reduction of Er(iii) and Al(iii), Al3Er2, Al2Er and AlEr were formed. In a La(iii) and Bi(iii) co-existing system in LiCl–KCl melts, LaBi2, LaBi and Li3Bi were the major products as a result of co-reduction.

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