A phenoxy-bridged trinuclear Ni(ii) complex: synthesis, structural elucidation and molecular docking with viral proteins

A novel phenoxy-bridged trinuclear nickel(ii) complex [Ni3(mu-L)2(bipy)3](1) (where H3L= (E)-2-hydroxy-N-(2-hydroxy-3,5-diiodophenyl)-3,5-diiodobenzohydrazonic acid, bipy = 2,2'-bipyridyl) has been designed and synthesized as a potential antivirus drug candidate. The trinuclear Ni(ii) complex [Ni3(mu-L)2(bipy)3](1) was fully characterized via single crystal X-ray crystallography. The unique structure of the trinuclear nickel(ii) complex crystallized in a trigonal crystal system with P3221 space group and revealed distorted octahedral coordination geometry around each Ni(ii) ion. The X-ray diffraction analysis established the existence of a new kind of trinuclear metal system containing nickel(ii)-nickel(ii) interactions with an overall octahedral-like geometry about the nickel(ii) atoms. The non-bonded Ni-Ni distance seems to be 3.067 and 4.455 A from the nearest nickel atoms. The detailed structural analysis and non-covalent supramolecular interactions are also investigated by single crystal structure analysis and computational approaches. Hirshfeld surfaces (HSs) and 2D fingerprint plots (FPs) have been explored in the crystal structure to investigate the intermolecular interactions. The preliminary analysis of redox and magnetic characterization was conducted using cyclic voltammetry measurements and a vibrating sample magnetometer (VSM), respectively. This unique structure shows good inhibition performance for SARS-CoV-2, Omicron and HIV viruses. For insight into the potential application of the Ni(ii) coordination complex as an effective antivirus drug, we have examined the molecular docking of the trinuclear Ni(ii) complex [Ni3(mu-L)2(bipy)3](1) with the receptor binding domain (RBD) from SARS-CoV-2 (PDB ID: 7MZF), Omicron BA.3 variant spike (PDB ID: 7XIZ), and HIV protease (PDB ID: 7WCQ) viruses. This structure shows good inhibition performance for SARS-CoV-2, Omicron S protein and HIV protease viruses;the binding energies (DELTAG) and the respective Ki/Kd (inhibition/dissociation constants) correlation values are -8.9 (2.373 muM or 2373 nM), -8.1 (1.218 muM or 1218 nM) and -7.9 (0.874 muM or 874 nM), respectively. The results could be used for rational drug design against SARS-CoV-2 Omicron variant and HIV protease viruses.Copyright © 2023 The Royal Society of Chemistry.

In Situ Electrochemical Trapping and Unraveling the Mechanism of the Toxic Intermediate Metabolite N-Acetyl-p-Benzoquinone Imine of the Acetaminophen Drug and Its Biomimetic Mediated NADH Oxidation Reaction

The integrative study of the pharmacokinetics and dynamics of a drug has been of great research interest due to its authentic description of the biomedical and clinical pros and cons. Acetaminophen (N-acetyl-4-aminophenol, AcAP) is a well-known analgesic having a high therapeutic value, including the Covid-19 treatment. However, an overdose of the drug (>200 mg/kg of men) can lead to liver toxicity. An intermediate, N-acetyl-p-benzoquinone imine (NAPQI), metabolite formation has been found to be responsible for the toxicity. For the detection of NAPQI, several ex situ techniques based on electrochemical methods followed by nuclear magnetic resonance, high-performance liquid chromatography, and LC-MS were stated. For the first time, we report an in situ electrochemical approach for AcAP oxidation and NAPQI intermediate (Mw = 149.1 g mol-1) trapping on a graphitic nanomaterial, carbon black (CB)-modified electrode in pH 7 phosphate buffer solution (CB@NAPQI). The NAPQI-trapped electrode exhibited a surface-confined redox peak at E°′ = 0.350 ± 0.05 V vs Ag/AgCl with a surface excess value of 3.52 n mol cm-2. Physicochemical characterizations by scanning electron microscopy, Raman, FTIR, and in situ electrochemical quartz crystal microbalance (EQCM) techniques supported the entrapment of the molecular species. Furthermore, the scanning electrochemical microscopy (SECM) technique has been adopted for surface-mapping the true active site of the NAPQI-trapped electrode. As a biomimetic study, the mediated oxidation reaction of NADH by CB@NAPQI was demonstrated, and the mechanistic and quantitative aspects were studied using cyclic voltammetry, rotating disc electrode, amperometry, and flow injection analysis techniques. © 2023 American Chemical Society.

Development of Aptasensor for the Diagnosis of Covid-19

Objectives: The objective is to develop a low-cost, practical, portable aptasensor platform for the diagnosis of COVID-19. Materials -Methods: Amino-terminated aptamers to be used for the design of an aptasensor were synthesized by SELEX method, and interaction of aptamers with SARS-CoV-2 S1 protein was investigated by isothermal titration calorimetry (ITC). Gold electrodes were used to design the biosensor platform. After the electrode surface was functionalized with cysteamine, the amino-terminated aptamer was conjugated to the surface via glutaraldehyde crosslinker. Then, the surface characterization and analytical parameters of the designed sensing platform were determined by adding commercial S1 proteins on the surface using differential pulse voltammetry (DPV), cyclic voltammetry (CV) and impedance spectroscopy (EIS). To evaluate the working performance of the system, S1 proteins were added to the synthetic serum samples using the standard addition method and the measurements were repeated. Result(s): Surface characterization of the platform designed with EIS and CV measurements was performed and it was found that the modification was successfully performed. In addition, DPV results and analytical parameters of the platform (calibration plot, limit of detection(LOD) , repeatability, coefficient of variation) were determined and the working performance of system was evaluated. Moreover, working performance of the biosensor in real samples and its specificity for COVID -19 were determined by experiments with synthetic serum and influenza A and B proteins. Conclusion(s): According the results, the system has potential to be used for the detection of COVID -19, and also it can be rapidly adapted in different pandemic situations that may occur in the future.

New bi-phosphonate derivative: Synthesis, characterization, antioxidant activity in vitro and via cyclic voltammetry mode and evaluation of its inhibition of SARS-CoV-2 main protease.

In this study, we have synthesized a new molecule labeled HBPA. Its molecular structure was determined by spectroscopic methods such as: FT-IR, NMR (1H, 13C and 31P); our compound is subjected to two antioxidant activities assays: DPPH scavenging and ferric reducing antioxidant power (FRAP); in the results, HBPA was expanded remarkable inhibition when compared especially to standard BHT with values of 14.936±0.808 and 7.1486±0.0645 µg/ml, respectively; in addition to the scavenging test of superoxide anion integrated in electrochemical process, it elucidated a strongly stable interaction towards the radical by evaluating the thermodynamic descriptors (Gibbs free energy ΔG° and the binding constant Kb). Besides, the electrochemical behavior of HBPA was distinguished by an irreversible system and for the electrochemical regime adopted at the surface of the electrode; a diffusion governed by a slow charge transfer was deduced. The molecular docking of HBPA was conducted beside Chloroquine and the obtained results were indicated a significant binding with active sites of the SARS-CoV-2 main protease (Mpro).

Molecularly imprinted polymer-modified carbon paste electrodes (MIP-CPE): A review on sensitive electrochemical sensors for pharmaceutical determinations

Recent years have been associated with the development of various sensor-based technologies in response to the undeniable need for the rapid and precise analysis of an immense variety of pharmaceuticals. In this regard, special attention has been paid to the design and fabrication of sensing platforms based on electrochemical detection methods as they can offer many advantages, such as portability, ease of use, relatively cheap instruments, and fast response times. Carbon paste electrodes (CPEs) are among the most promising conductive electrodes due to their beneficial properties, including ease of electrode modification, facile surface renewability, low background currents, and the ability to modify with different analytes. However, their widespread use is affected by the lack of sufficient selectivity of CPEs. Molecularly imprinted polymers (MIPs) composed of tailor-made cavities for specific target molecules are appealing complementary additives that can overcome this limitation. Accordingly, adding MIP to the carbon paste matrix can contribute to the required selectivity of sensing platforms. This review aims to present a categorized report on the recent research and the outcomes in the combinatory fields of MIPs and CPEs for determining pharmaceuticals in complex and simple matrices. CPEs modified with MIPs of various pharmaceutical compounds, including analgesic drugs, antibiotics, antivirals, cardiovascular drugs, as well as therapeutic agents affecting the central nervous system (CNS), will be addressed in detail.Copyright © 2023 Elsevier B.V.

Binding-Induced Folding of DNA Oligonucleotides Targeted to the Nucleocapsid Gene Enables Electrochemical Sensing of SARS-CoV-2.

In the wake of the COVID-19 pandemic, millions of confirmed cases and deaths have been reported around the world. COVID-19 spread can be slowed and eventually stopped by a rapid test to diagnose positive cases of the disease on the spot. It is still important to test for COVID-19 quickly regardless of the availability of the vaccine. Using the binding-induced folding principle, we developed an electrochemical test for detecting SARS-CoV-2 with no RNA extraction or nucleic acid amplification. The test showed high sensitivity with a limit of detection of 2.5 copies/µL. An electrode mounted with a capture probe and a portable potentiostat are used to conduct the test. To target the N-gene of SARS-CoV-2, a highly specific oligo-capturing probe was used. Based on the binding-induced "folding" principle, the sensor detects binding between the oligo and RNA. When the target is absent, the capture probe tends to form a hairpin as a secondary structure, retaining the redox reporter close to the surface. This can be seen as a large anodic and cathodic peak current. When the target RNA is present, the hairpin structure will open to hybridize with its complementary sequence, causing the redox reporter to pull away from the electrode. Consequently, the anodic/cathodic peak currents are reduced, indicating the presence of the SARS-CoV-2 genetic material. Validation of the test performance was performed using 122 COVID-19 clinical samples (55 positives and 67 negatives) and benchmarked to the gold standard reverse transcription-polymerase chain reaction (RT-PCR) test. As a result of our test, the accuracy, sensitivity, and specificity have been measured at 98.4%, 98.2%, and 98.5%, respectively.

Electrochemical Biosensor for the Determination of Specific Antibodies against SARS-CoV-2 Spike Protein.

In this article, we report the development of an electrochemical biosensor for the determination of the SARS-CoV-2 spike protein (rS). A gold disc electrode was electrochemically modified to form the nanocrystalline gold structure on the surface. Then, it was further altered by a self-assembling monolayer based on a mixture of two alkane thiols: 11-mercaptoundecanoic acid (11-MUA) and 6-mercapto-1-hexanol (6-MCOH) (SAMmix). After activating carboxyl groups using a N-(3-dimethylaminopropyl)-N'-ethyl-carbodiimide hydrochloride and N-hydroxysuccinimide mixture, the rS protein was covalently immobilized on the top of the SAMmix. This electrode was used to design an electrochemical sensor suitable for determining antibodies against the SARS-CoV-2 rS protein (anti-rS). We assessed the association between the immobilized rS protein and the anti-rS antibody present in the blood serum of a SARS-CoV-2 infected person using three electrochemical methods: cyclic voltammetry, differential pulse voltammetry, and potential pulsed amperometry. The results demonstrated that differential pulse voltammetry and potential pulsed amperometry measurements displayed similar sensitivity. In contrast, the measurements performed by cyclic voltammetry suggest that this method is the most sensitive out of the three methods applied in this research.

The First Electroanalytical Study Of Umifenovir (Arbidol) Used As A Potential Antiviral Drug For The Treatment of SARS-CoV-2: A Voltammetric Quantification On The Boron-Doped Diamond Electrode By Using Anionic Surfactant Media

In this work, an electroanalytical procedure for sensing umifenovir (arbidol) by square wave adsorptive stripping voltammetry (SW-AdSV) was developed utilizing an anodically pretreated boron-doped diamond electrode. Measurements of umifenovir using cyclic voltammetry with phosphate buffer solution (PBS, 0.1 M, pH 2.5) revealed irreversible behaviour, adsorption-controlled as well as an ill-defined (+1.13 V, PA1) and a well-defined (+1.47 V, PA2) two oxidation peaks. Umifenovir oxidations depend critically on supporting electrolytes and pH. The second oxidation peak (PA2) current of the umifenovir was enhanced by adding sodium dodecyl sulfate (SDS, anionic surfactant) in the chosen supporting electrolyte. Umifenovir was quantified using its second oxidation peak (PA2) at about +1.39 V. Using the optimized condition, the oxidation peak current of PA2 showed a linear relationship for umifenovir determination in the concentration range from 0.005 to 1.0 μg ml−1 (9.73 × 10−9−1.95 × 10−6 M), with a detection limit of 0.0014 μg ml−1 (2.72 × 10−9 M) in PBS (PH 2.5) with SDS. Finally, the developed approach was successfully utilized to determine umifenovir in the pharmaceutical formulation and urine samples. To the best of our knowledge, this is the first electroanalytical approach for voltammetric sensing of umifenovir. © 2023 The Electrochemical Society ("ECS”). Published on behalf of ECS by IOP Publishing Limited

New Ni(II) and Cu(II) Schiff base coordination complexes derived from 5-Bromo-salicylaldehyde and 3-picoyl amine/ethylenediamine: Synthesis, structure, Hirshfeld surface and molecular docking study with SARS-CoV-2 7EFP-main protease

Two co-ordination compounds, one nickel(II) complex [Ni(L1)(Phen)2]ClO4 (1) and one copper(II) complex [Cu(L2)] (2), were synthesized using Schiff base ligands derived from the condensation reaction of 5-Bromo-salicylaldehyde with 3-picoyl amine (L1H)(L1H = (E)-4-Bromo-2-(((pyridin-3-ylmethylene)amino) methyl) phenol) and ethylenediamine (L2H2), respectively(L2H2 = 2,2′-((1E,1′E)-(ethane-1,2-diylbis(azaneylylidene))bis(methanelylidene))bis (4-bromophenol)). The newly synthesized complexes were fully characterized, including X-ray crystallography. The crystal structure of both the complexes was determined using Single Crystal structure analysis. The electrochemical properties of (1) were studied using cyclic voltammetry. DFT calculations were done for the newly synthesized co-ordination complexes to have a relevant and reasonably accurate calculation of their molecular and electronic behavior. The Hirshfeld surface (HS) analysis was also performed using the crystallographic data for investigating the nature and quantitative contribution of all possible non-covalent intermolecular interactions within the crystal lattice. To explore potential SARS-CoV-2 drug candidates, both the co-ordination compounds were subjected to molecular docking calculations with the SARS-CoV-2 virus (PDB ID: 7EFP). The molecular docking calculations of Ni(II) complex (1) into the 7EFP-main protease of SARS-CoV-2 virus revealed the binding energy of −11.5 kcal/mol, while Cu(II) complex (2) exhibited the binding energy of −8.5 kcal/mol at the inhibition binding site of the receptor protein.

Preface for the 66th Special Feature "Novel Aspects and Approaches to Experimental Methods for ElectrochemistryӠ

The Kansai Branch of the Electrochemical Society of Japan publishes a collection of papers in Electrochemistry, which serve as a commentary to the 51st Electrochemistry Workshop. This attempt is motivated by the fact that the domestic seminars are now widely publicized through the on-demand event triggered by COVID-19. This preface consists of the significance of the publication and an introduction of the lecturers as a part of special future for "Novel Aspects and Approaches to Experimental Methods for Electrochemistry.” in this issue of Electrochemistry. © 2022 Electrochemical Society of Japan. All rights reserved.

The 66th special feature "Novel Aspects and Approaches to Experimental Methods for Electrochemistry"

The Kansai Branch of the Electrochemical Society of Japan publishes a collection of papers in Electrochemistry, which serve as a commentary to the 51st Electrochemistry Workshop. This attempt is motivated by the fact that the domestic seminars are now widely publicized through the on-demand event triggered by COVID-19. This preface consists of the significance of the publication and an introduction of the lecturers as a part of special future for "Novel Aspects and Approaches to Experimental Methods for Electrochemistry." in this issue of Electrochemistry. (C) The Author(s) 2022. Published by ECSJ.

Voltammetric determination of Molnupiravir used in treatment of the COVID-19 at magnetite nanoparticle modified carbon paste electrode.

To reduce the progression of the viral process in patients infected with COVID-19, new treatments and drug active substances are needed. One of these drugs is Molnupiravir (MNP) which has a direct antiviral effect and has also proven to be highly effective in reducing the azopharyngeal SARS-CoV-2 infectious virus and viral RNA. Due to the importance and frequent use of this drug in the treatment of COVID-19, its accurate, quick, and cheap detection in pharmaceutical or biological samples is crucial. In this work, electrochemical behavior and sensitive voltammetric determination of MNP are described using a magnetite nanoparticle modified carbon paste electrode (Fe3O4@CPE) for the first time. Fe3O4 nanoparticles (NPs) were characterized by recording their transmission electron microscopy (TEM) images, energy dispersive X-ray (EDX), and X-ray diffraction (XRD) spectra. Cyclic voltammetric measurements showed that MNP was irreversibly oxidized at Fe3O4@CPE at 760 mV in pH 2.0 Britton Robinson buffer solution (BRBS). The peak current of MNP was increased approximately threefold at Fe3O4@CPE compared to bare CPE due to a good electrocatalytic efficiency of Fe3O4 NPs. According to differential pulse voltammetric studies, the fabricated electrode exhibited a linear range (LR) between 0.25 and 750 µM with sensitivity and limit of detection (LOD) of 4591.0 µA mM-1 cm-2 and 0.05 µM, respectively. On the other hand, although lower sensitivity (327.3 µA mM-1 cm-2) was obtained from CV compared to DPV, a wider linear calibration curve between 0.25 and 1500 µM was obtained in CV. Studies performed in tablet samples confirmed that the Fe3O4@CPE exhibits high applicability for selective and accurate voltammetric determination of MNP in real samples.

Electrochemical Determination of Anti Covid-19 Drug Favipiravir by Voltammetric Techniques

For the first time, Favipiravir electrochemical behavior was investigated using voltammetry at a Glassy carbon electrode. Through the use of Cyclic voltammetry,Differential pulse voltammetry, and Square wave voltammetry approaches, the electrochemical behavior of (FAV) was novelty diagnosed in three different ways. The scan rate investigation in the range of 0.01-10 V/s reveals that the process is an electrode process that is completely irreversible and that the oxidation of FAV on the surface of GCE is diffusion controlled. (FAV) demonstrated an irreversible oxidation peak at about +1.402 V at Glassy carbon electrode. The best experimental conditions for the voltammetric determination of FAV at GCE have been achieved through the investigation of optimal operational parameters and the impacts of experimental conditions.The SWV oxidative peak current showed excellent linear dependency on FAV concentration in the region of 10-100 ppm, with limits of detection (LOD) and quantitation (LOQ) of 0.108 and 0.362 ppm, respectively. Additionally, for the analysis of FAV in pharmaceutical tablet and real samples, remarkable recovery findings were attained. The suggested method was successfully used to determine FAV in pharmaceutical and actual sample. The unique studied method does not require sample preparation and is quick and inexpensive. Copyright © 2022, Anka Publishers. All rights reserved.

Antioxidant Capacity of Herzegovinian Wildflowers Evaluated by UV-VIS and Cyclic Voltammetry Analysis.

Considering the vast cultural and traditional heritage of the use of aromatic herbs and wildflowers for the treatment of light medical conditions in the Balkans, a comparison of the antioxidant capacity of wildflowers extracts from Herzegovina was studied using both cyclic voltammetry and spectrophotometry. The cyclic voltammograms taken in the potential range between 0 V and 800 mV and scan rate of 100 mV s-1 were used for the quantification of the electrochemical properties of polyphenols present in four aqueous plant extracts. Antioxidant capacity expressed as mmoL of gallic acid equivalents per gram of dried weight of the sample (mmoL GAE g-1 dw) was deduced from the area below the major anodic peaks (Q400 pH 6.0, Q500 pH 4.7, Q600 pH 3.6). The results of electrochemical measurements suggest that the major contributors of antioxidant properties of examined plants are polyphenolic compounds that contain ortho-dihydroxy-phenol or gallate groups. Using Ferric reducing-antioxidant power (FRAP) and 2,2'-azino-bis spectrophotometric methods (3-ethylbenzthiazoline-6-sulphonic acid) radical cation-scavenging activity (ABTS) additionally determined antioxidant capacity. The FRAP results ranged from 2.9702-9.9418 mmoL Fe/g dw, while the results for ABTS assays expressed as Trolox equivalents (TE) ranged from 14.1842-42.6217 mmoL TE/g dw. The Folin-Ciocalteu procedure was applied to determine the total phenolics content (TP). The TP content expressed as Gallic acid equivalents (GAE) ranged from 6.0343-9.472 mmoL GAE/g dw. The measurements of total flavonoid (TF) and total condensed tannin (TT) contents were also performed to obtain a broader polyphenolic profile of tested plant materials. Origanum vulgare L. scored the highest on each test, with the exception of TT content, followed by the Mentha × piperita L., Artemisia annua L., and Artemisia absinthium L., respectively. The highest TT content, expressed as mg of (-)catechin equivalents per gram of dried weight of sample (mg CE/g dw), was achieved with A. absinthium extract (119.230 mg CE/g dw) followed by O. vulgare (90.384 mg CE/g dw), A. annua (86.538 mg CE/g dw) and M. piperita (69.231 mg CE/g dw), respectively. In addition, a very good correlation between electrochemical and spectroscopic methods was achieved.

Strategies for sensitivity enhancement of point-of-care devices

Point-of-care (POC) technology reduces the time required for diagnosis at a reduced cost to facilitate early treatment, continuous monitoring, and prevention of fatal outcomes. Biosensors are the key to the development of reliable and accurate POC devices as they are capable of detecting clinical biomarkers based on bio-recognition events. Paper-based microfluidics and lateral flow assays (LFAs) are the most commonly used techniques for the development of POC devices. Electrochemical biosensors provide high sensitivity and reproducibility in comparison to optical biosensors. Sensitivity enhancement of POC devices is imperative to lower their detection limit for improved analysis of target biomarkers at low concentrations. In this review, we have discussed the need for sensitivity enhancement in POC devices. Various sensitivity enhancement strategies such as physical, chemical, electrochemical, nanomaterial, nucleic acid, enzymatic, label-based, etc. are discussed along with numerous examples. The role of biosensors in the sensitivity enhancement of POC devices is also described herein. We have illustrated the relationship between sensitivity and the limit of detection of POC devices. Several sensitivity enhancement strategies that have been either adopted or have the potential to be realized for POC devices have been summarized in tabular form. In terms of future perspectives, the sensitivity enhancement of POC devices for the detection of important biomarkers is yet to be comprehended copiously amid the rising market for POC devices.

Determination of rSpike Protein by Specific Antibodies with Screen-Printed Carbon Electrode Modified by Electrodeposited Gold Nanostructures.

In this research, we assessed the applicability of electrochemical sensing techniques for detecting specific antibodies against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) spike proteins in the blood serum of patient samples following coronavirus disease 2019 (COVID-19). Herein, screen-printed carbon electrodes (SPCE) with electrodeposited gold nanostructures (AuNS) were modified with L-Cysteine for further covalent immobilization of recombinant SARS-CoV-2 spike proteins (rSpike). The affinity interactions of the rSpike protein with specific antibodies against this protein (anti-rSpike) were assessed using cyclic voltammetry (CV) and differential pulse voltammetry (DPV) methods. It was revealed that the SPCE electroactive surface area increased from 1.49 ± 0.02 cm2 to 1.82 ± 0.01 cm2 when AuNS were electrodeposited, and the value of the heterogeneous electron transfer rate constant (k0) changed from 6.30 × 10-5 to 14.56 × 10-5. The performance of the developed electrochemical immunosensor was evaluated by calculating the limit of detection and limit of quantification, giving values of 0.27 nM and 0.81 nM for CV and 0.14 nM and 0.42 nM for DPV. Furthermore, a specificity test was performed with a solution of antibodies against bovine serum albumin as the control aliquot, which was used to assess nonspecific binding, and this evaluation revealed that the developed rSpike-based sensor exhibits low nonspecific binding towards anti-rSpike antibodies.

Electrochemical Determination of Interaction between SARS-CoV-2 Spike Protein and Specific Antibodies.

The serologic diagnosis of coronavirus disease 2019 (COVID-19) and the evaluation of vaccination effectiveness are identified by the presence of antibodies specific to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). In this paper, we present the electrochemical-based biosensing technique for the detection of antibodies specific to the SARS-CoV-2 proteins. Recombinant SARS-CoV-2 spike proteins (rSpike) were immobilised on the surface of a gold electrode modified by a self-assembled monolayer (SAM). This modified electrode was used as a sensitive element for the detection of polyclonal mouse antibodies against the rSpike (anti-rSpike). Electrochemical impedance spectroscopy (EIS) was used to observe the formation of immunocomplexes while cyclic voltammetry (CV) was used for additional analysis of the surface modifications. It was revealed that the impedimetric method and the elaborate experimental conditions are appropriate for the further development of electrochemical biosensors for the serological diagnosis of COVID-19 and/or the confirmation of successful vaccination against SARS-CoV-2.

NanoStat: An open source, fully wireless potentiostat

We present an open source, fully wireless potentiostat (the “NanoStat”) for applications in electrochemistry, sensing, biomedical diagnostics, and nanotechnology, based on only 2 integrated circuit chips: A digital microcontroller with integrated on board WiFi and file/web server hardware/software, and an analog front end. This versatile platform is fully capable of all modern electrochemisty assays, including cyclic voltammetry, square wave voltammetry, chronoamperometry, and normal pulse voltammetry. The user interface is a web browser connected over http. All the code (firmware, HTML5, JavaScript) is hosted by the NanoStat itself without the need for any additional software. The total size is 4×40×20 mm and battery operation for 6 h is demonstrated, possible to extend to weeks or months in sleep mode. We anticipate that the applications of this could be very broad, from biomedical sensing in the clinic, to remote monitoring of unattended “motes”, to even possibly sensing aerial pathogens such as COVID in large public spaces without the need for anything other than a web browser for remote monitoring from anywhere in the world. Finally, we propose to use this software suite as a basis (kernel) of a fully open source, general purpose, web based electrochemistry software suite, ed from the hardware, which we call “OpenEChem”. © 2022

Determination of Ascorbic Acid in Pharmaceuticals and Food Supplements with the New Potassium Ferrocyanide-Doped Polypyrrole-Modified Platinum Electrode Sensor

This paper reports the results obtained from the determination of ascorbic acid with platinum-based voltammetric sensors modified with potassium hexacyanoferrate-doped polypyrrole. The preparation of the modified electrodes was carried out by electrochemical polymerization of pyrrole from aqueous solutions, using chronoamperometry. Polypyrrole films were deposited on the surface of the platinum electrode, by applying a constant potential of 0.8 V for 30 s. The thickness of the polymer film was calculated from the chronoamperometric data, and the value was 0.163 μm. Cyclic voltammetry was the method used for the Pt/PPy-FeCN electrode electrochemical characterization in several types of solution, including KCl, potassium ferrocyanide, and ascorbic acid. The thin doped polymer layer showed excellent sensitivity for ascorbic acid detection. From the voltammetric studies carried out in solutions of different concentrations of ascorbic acid, ranging from 1 to 100 × 10−6 M, a detection limit of 2.5 × 10−7 M was obtained. Validation of the analyses was performed using pharmaceutical products with different concentrations of ascorbic acid, from different manufacturers and presented in various pharmaceutical forms, i.e., intravascular administration ampoules, chewable tablets, and powder for oral suspension.

Determination of Zinc Level in Serum and Urine of COVID-19 Patients by New Metal Oxide Nanoparticles Carbon Paste Electrode

Introduction: Zinc is one of the most essential bio-elements, especially when it comes to the human body’s defence against viral or bacterial invaders, for individuals infected with Coronavirus, many experts recommend taking zinc supplements. Method: To assess the amount of zinc in the blood and urine of the wounded patients, a novel analytical technique with high purity and sensitivity is needed. It must also be affordable, short-time and waste less and not take a long time to analyse. Results: Zinc oxide nanoparticles are used to fabricate an electrode with excellent sensitivity and selectivity for zinc ions. Conclusion: Finally, after testing, it was shown that utilising the cyclic voltammetry technique, zinc oxide nanoparticles carbon past electrode were very sensitive and selective in detecting minute changes in current caused by both the reduction and oxidation processes in COVID patients. Variations in the surrounding environment were also examined for optimum results. Copyright (c) 2022: Author(s).