Electrochemical Sensor Research Articles

Thiol-based chemically modified carbon screen-printed electrode for simultaneous quantification of trace level Pb(II) and Cd(II).

Present work reports, the development of a novel electrochemical sensor based on a diazonium-coupling reaction and covalent attachment of the -NH2 group of cysteamine (Cyst) on screen-printed carbon electrode (SPCE), for simultaneous determination of Pb(II) and Cd(II). Initially, the in-situ generated 4-carboxyphenyl (4-CP) diazonium salt was electro-grafted to generate 4-CP/SPCE, followed by covalent bonding of terminal carboxylic group of 4-CP with -NH2 group of Cyst to give Cyst/4-CP/SPCE. The modified electrode showed an enhanced selectivity and sensitivity toward the quantification of Pb(II) and Cd(II) using square wave anodic stripping voltammetry (SWASV) without mutual interference. Under optimal experimental conditions, the newly designed sensor showed a wide linear range of 0.01µM to 0.7µM. The limit of detection (LOD) obtained was 0.882nM (0.09 ppb) and 0.65nM (0.134ppb) for Cd(II) and Pb(II), respectively. The modified SPCE exhibited good stability, selectivity, and reproducibility. Furthermore, the sensor was successfully applied for the determination of Pb(II) and Cd(II) ions in water samples which illustrated excellent recoveries in different spiked samples and the results were in line with the standard ICP-AES analysis.

A Novel MXene@MOF@Pt NPs-Based Enzyme-Free Electrochemical Sensor for highly Sensitive Detection of Hydrogen Peroxide Released from Living Cells

A Novel MXene@MOF@Pt NPs-Based Enzyme-Free Electrochemical Sensor for highly Sensitive Detection of Hydrogen Peroxide Released from Living Cells

Nucleic acid aptamer-based electrochemical sensor for the detection of serum P-tau231 and the instant screening test of Alzheimer's disease.

The instant screening of patients with a tendency towards developing Alzheimer's disease (AD) is significant for providing preventive measures and treatment. However, the current imaging-based technology cannot meet the requirements in the early stage. Developing biosensor-based liquid biopsy technology could be overcoming this bottleneck problem. Herein, we developed a simple, low-cost, and sensitive electrochemical aptamer biosensor for detecting phosphorylated tau protein threonine 231 (P-tau231), the earliest and one of the most efficacious abnormally elevated biomarkers of AD. Gold nanoparticles (AuNPs) were electrochemically synthesized on a glassy carbon electrode as the transducer, exhibiting excellent conductivity, and were applied to amplify the electrochemical signal. A nucleic acid aptamer was designed as the receptor to capture the P-tau231 protein, specifically through the formation of an aptamer-antigen complex. The proposed biosensor showed excellent sensitivity in detecting P-tau 231, with a broad linear detection range from 10 to 107pg/mL and a limit of detection (LOD) of 2.31pg/mL. The recoveries of the biosensor in human serum ranged from 97.59 to 103.26%, demonstrating that the biosensor could be used in complex practical samples. In addition, the results showed that the developed biosensor has good repeatability, reproducibility, and stability, which provides a novel method for the early screening of AD.

Molecularly Imprinted Polymer-Based Electrochemical Sensor for the Detection of Azoxystrobin in Aqueous Media

Molecularly Imprinted Polymer-Based Electrochemical Sensor for the Detection of Azoxystrobin in Aqueous Media

Green Electrochemical Sensing: Novel Ion-Selective Electrode Method for Precise Determination of Dimenhydrinate and its Metabolite along with Cinnarizine in Pharmaceutical and Plasma Samples

Green Electrochemical Sensing: Novel Ion-Selective Electrode Method for Precise Determination of Dimenhydrinate and its Metabolite along with Cinnarizine in Pharmaceutical and Plasma Samples

Application of Graphdiyne Confined Gold Nanoparticles Modified Electrode as A Robust Sensing Platform for The Detection of 7-Hydroxy-6-methoxy-hydrocoumarin

Abstract A graphdiyne (GDY) and gold nanoparticles (AuNPs) nanocomposite was formed with AuNPs growing on the surface and between the layers of GDY, which was used as the sensing interface on carbon ionic liquid electrode (CILE) to detect 7-hydroxy-6-methoxy-hydrocoumarin (7-6-HDC) that isolated from the noni juice. The GDY-Au nanocomposite was characterized by different spectroscopic techniques, which exhibited corrugated and folded morphology with large specific surface area. The GDY-Au nanocomposite modified electrode displayed excellent performance which is attributed to the highly conductive nanocomposite, where GDY structure with defects could immobilize more AuNPs to decrease the electron transfer resistance. In addition, the reaction mechanism of 7-6-HDC at GDY-Au surface was deduced based on the electrochemical kinetics investigations. Combined with density functional theory calculation, it was verified that the active site of 7-6-HDC and the presence of AuNPs enhanced the electrocatalytic capacity of GDY-Au nanocomposite. Under optimal conditions, the modified electrode displayed a wider linear range from 10.0 nM to 1.0 mM for 7-6-HDC analysis with a detection limit of 3.22 nM (3S0/S). This work provides a promising material to realize accurate analysis for 7-6-HDC, and the discovered sensing mechanism provides method guidance for the exploration of other novel electrochemical sensors.

A novel electrochemical sensor based on a Cu-coordinated molecularly imprinted polymer and MoS2 modified chitin-derived carbon for selective detection of dextromethorphan.

Dextromethorphan (DXM) is a widely utilized central antitussive agent, which is frequently abused by individuals seeking its recreational effect. But DXM overdose can cause some adverse effects, including brain damage, loss of consciousness, and cardiac arrhythmias, and hence its detection is significant. Herein, an electrochemical sensor based on a Cu-coordinated molecularly imprinted polymer (Cu-MIP) was fabricated for its detection. For constructing the sensor, nitrogen-doped carbon nanosheets (CCNs) were prepared through calcining chitin under an argon atmosphere, and molybdenum disulfide (MoS2) was allowed to grow on their surface. Subsequently, the obtained MoS2/CCNs composite was employed to modify a glassy carbon electrode (GCE), and the Cu-MIP was electrodeposited on the electrode in a Cu-1,10-phenanthroline (Cu-Phen) solution containing DXM, where Cu2+ played a role in facilitating electron transfer and binding DXM. Due to the large specific surface area, good electrocatalytic properties and recognition of the resulting composite, the resulting Cu-MIP/MoS2/CCNs/GCE showed high selectivity and sensitivity. Under optimized experimental conditions, the peak current of DXM and its concentration exhibited a good linear relationship over the concentration range of 0.1-100 μM, and the limit of detection (S/N = 3) was 0.02 μM. Furthermore, the electrochemical sensor presented good stability, and it was successfully used for the determination of DXM in pharmaceutical, human serum and urine samples.

Development of Lab-made Flexible Screen-printed Electrode based on S-Graphene Enriched with AuNPs and CuO for Electrochemical Detection of Tyrosine

Abstract Tyrosine (Tyr) is an amino acid that serves as a precursor for the synthesis of numerous neurotransmitters in the human body. This study aimed to design paper-based lab-made screen-printing electrodes (SPE) for tyrosine determination using a flexible electrochemical sensor. To achieve this, conductive inks with this composition were developed for the first time in the literature by incorporating sulfur (S)-doped graphene, synthesized using Yucel's method, as well as gold nanoparticles and copper oxide (CuO) as conductive fillers, which were then integrated into flexible paper substrates. The optimized electrodes (CuO/S-G/AuNPs/SPE) were used to investigate the best oxidation response to tyrosine. Characterization of CuO/S-G/AuNPs/SPE was performed using electrochemical impedance spectroscopy, Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, and field emission scanning electron microscopy. The sensor had a limit of detection of 0.024 µM and a limit of quantitation of 0.08 µM. In addition, the sensor's affordability and ease of use make it advantageous for practical applications. The results demonstrate the sensor's stability and reproducibility in measuring tyrosine. It is anticipated that the proposed sensor can effectively detect tyrosine in sweat samples and serve as a non-invasive, wearable, flexible sensor in the future.

Electrochemical determination of theophylline using a nickel ferrite/activated carbon-modified electrode

Abstract In this work, a nanocomposite based on nickel ferrite/activated carbon (NiF/AC) was used to modify a highly sensitive electrochemical sensor for the quantification of theophylline (TPL) in pharmaceutical tablets. The synthesized materials were characterized using X-ray diffraction, Fourier transform infrared spectroscopy, scanning electron microscopy, energy dispersive X-ray spectroscopy-elemental mapping and surface area analysis via the Brunauer‒Emmett‒Teller method. Cyclic voltammetry was employed to study the electrocatalytic properties of the NiF/AC-GCE toward the oxidation of TPL. The dependence of the electrochemical response on the scan rate and pH was also investigated, and the working parameters were optimized. The linear range of the established electrochemical biosensor was from 0.5 to 5 μM (R2 = 0.997), with a detection limit of 0.21 μM. The present method was tested using three pharmaceutical formulation standard samples with good accuracy and acceptable recovery. Thus, it is a promising candidate for the determination of TPL in pharmaceutical formulations.

Electrochemical Sensor Modified with Graphene Oxide Decorated with Copper Oxide Nanoparticles for Velpatasvir’s Monitoring in Spiked Human Plasma.

Abstract Velpatasvir, an antiviral agent co-formulated with sofosbuvir used to treat hepatitis C, has recently demonstrated beneficial therapeutic effects against COVID-19. Therefore, therapeutic drug monitoring of velpatasvir is essential to achieve the desired clinical outcomes. An electrochemical sensor modified with synthesized copper oxide nanoparticles on the surface of graphene oxide (CuO/GO-NPs) was fabricated for the analysis of velpatasvir for the first time. Characterization was carried out using Fourier-transform infrared spectroscopy, X-ray diffraction, and scanning electron microscopy with energy-dispersive X-ray spectroscopy. The voltammetric determinations were conducted using differential pulse and cyclic voltammetry, where the modified electrode exhibited better sensitivity than the unmodified one. The method was validated according to the International Council for Harmonisation (ICH) guidelines, exhibiting linearity within a range of 1.0 ×10-7 – 1.0 × 10-5 M, covering velpatasvir’s maximum plasma concentration (Cmax), with a quantification limit of 2.89 × 10-7 M and a detection limit of 9.03 × 10-8 M. The developed sensor was successfully applied to spiked human plasma at velpatasvir’s Cmax level. The method’s greenness was assessed using the Analytical Eco-scale and the Green analytical procedure index tools. This method holds promise as a green simple approach to implemented in future velpatasvir’s therapeutic drug monitoring studies.

Development of a chitosan-gold nanocomposite based disposable pencil graphite electrode for the selective detection of thiram in peach juice

ABSTRACT Hazardous chemicals that are mostly employed in modern agriculture for pest management have caused long-term environmental accumulation as well as major issues with food safety and human health. So, there is an urgent demand for efficient detection methods for environmental monitoring. To do this, the most contemporary electrochemical sensor technology is suggested. In this study, a new electrochemical sensor has been developed to detect thiram (Th) fungicide, utilising a modified activated pencil graphite electrode (a-PGE) made from chitosan-gold nanoparticle polymer (Ch-AuNPs) for the first time. The Ch-AuNPs/a-PGE surface has been characterised using cyclic voltammetry (CV), scanning electron microscopy (SEM), and energy dispersive X-ray spectroscopy (EDS). Following adjustments to experimental parameters, the proposed electrochemical sensor demonstrated a linear calibration curve within the range of 4.90–140 μM, displaying a rapid response to thiram with a detection limit of 1.15 μM. The sensor exhibited notable selectivity, stability, and reproducibility. To assess its practical utility, the sensor was applied to analyse thiram in peach juice, and the recovery process indicated its effectiveness as a practical, swift, and efficient tool in pesticide residue monitoring.

Manufacturing of TiO2, Al2O3 and Y2O3 Ceramic Nanotubes for Application as Electrodes for Printable Electrochemical Sensors

Manufacturing of TiO2, Al2O3 and Y2O3 Ceramic Nanotubes for Application as Electrodes for Printable Electrochemical Sensors

One-Pot Synthesis of Nanoflower-Like Zn2SnS4 as Nanozymes for Highly Sensitive Electrochemical Detection of H2O2 Released by Living Cells.

The sensitive and reliable nanozyme-based sensor enables the detection of low concentrations of H2O2 in biological microenvironments, it has potential applications as an in-situ monitoring platform for cellular H2O2 release. The uniformly dispersed bimetallic sulfide (Zn2SnS4) nanoflowers were synthesized via a one-pot hydrothermal method and the two kinds of metal ions can serve as morphology and structure directing agents for each other in the synthetic process. The nanoparticles were utilized as nanozyme materials to fabricate a novel electrochemical sensor, and it exhibits a distinct electrochemical response towards H2O2 with excellent stability and detection capability (with a minimum detection limit of 1.79 nM (S/N=3)), the excellent characteristics facilitate the precise detection of low concentrations of H2O2 in biological microenvironments. Use the macrophages differentiated from leukemia THP-1 cells as a representative sensing model, the sensor was successfully utilized for real-time monitoring of the release of H2O2 induced by living cells, which has significant potential applications in clinical diagnosis and cancer treatment.

Plant-based zinc nanoflowers assisted molecularly imprinted polymer for the design of an electrochemical sensor for selective determination of abrocitinib

The first electrochemical sensor application in the literature is described for the sensitive and selective determination of the selective Janus kinase (JAK)-1 inhibitor abrocitinib (ABR). ABR is approved by the U.S. Food and Drug Administration (FDA) for the treatment of atopic dermatitis. The molecularly imprinted polymer (MIP)-based sensor was designed to incorporate zinc nanoflower (ZnNFs)-graphene oxide (GO) conjugate (ZnNFs@GO), synthesized from the root methanolic extract (RME) of the species Alkanna cappadocica Boiss. et Bal. to improve the porosity and effective surface area of the glassy carbon electrode (GCE). Furthermore, the MIP structure was prepared using ABR as a template molecule, 4-aminobenzoic acid (4-ABA) as a functional monomer, and other additional components. Scanning electron microscopy (SEM), X-ray diffraction (XRD), and Fourier transform infrared spectroscopy (FTIR) were used to characterize the surface and structure of the synthesized nanomaterial and MIP-based surface. Among the electrochemical methods, cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) were preferred for detailed electrochemical characterization, and differential pulse voltammetry (DPV) was preferred for all other electrochemical measurements using 5.0 mM [Fe(CN)6]3–/4– solution as the redox probe. The MIP-based sensor, which was the result of a detailed optimization phase, gave a linear response in the 1.0 × 10–13 – 1.0 × 10–12 M range in standard solution and serum sample. The obtained limit of detection (LOD) and limit of quantification (LOQ) values and recovery studies demonstrated the sensitivity, accuracy, and applicability of the sensor. Selectivity, the most important feature of the MIP-based sensor, was verified by imprinting factor calculations using ibrutinib, ruxolitinib, tofacitinib, zonisamide, and acetazolamide.Graphical

Enhanced detection of heavy metal ions using Ag nanoparticles and single-walled carbon nanotubes within Cu-based metal-organic frameworks

Heavy metal ions (HMIs) are major water pollutants, and their toxicity for humans is a great concern for scientists and environmentalists. They are harmful to health even at trace levels; therefore, identifying and removing heavy metals from water is critical. Herein, we report highly selective and sensitive multi-analyte detection of HMIs in water using an electrochemical sensor probe based on Ag nanoparticles and single-walled carbon nanotubes incorporating copper benzene tri-carboxylate metal–organic frameworks (Ag/SWNTs@CuBTC-MOFs). The materials were characterized using FTIR, XPS, XRD, and FE-SEM with EDX mapping, TEM, TG-DTA, BET surface area, CV, and EIS. The Ag/SWNTs@CuBTC-MOF electrochemical sensor was tested by differential pulse voltammetry over a pH range of 3–10 for various HMIs. It shows high pH-dependent sensitivity towards Hg2+ (pH-5.0), Ni2+ (pH-7.0), and Fe3+ (pH-10.0) ions and a limit of detection of 1.39 nM, 2.6 nM, and 3.03 nM, respectively. The fabricated sensor probe exhibits high selectivity, good linearity, and a limit of detection below the maximum contamination limit, as the US Environmental Protection Agency suggested.

Surface-display Techniques in Electrochemical Biosensor Designs for Health Monitoring

Abstract Enzymatic and microbial electrochemical biosensors integrate enzymes and microorganisms as biological recognition elements into the sensor design and functionality. Enzyme-based sensors offer high sensitivity and selectivity for target analyte detection. However, these have limited stability necessary for continuous analyte monitoring. Contrarily, microbe-based electrochemical sensors provide a means for continuous analyte sensing but are associated with challenges related to analyte selectivity in complex samples. To address these limitations, surface-display methods, which bind enzymes to microbial surfaces, enhance biosensor selectivity and sensitivity. This perspective outlines the application of surface-display techniques, offering a promising avenue for health monitoring.

Electrochemical Performance of Polyaniline‐Polyvanadate‐Copper Nanomaterials for the Detection of Benzoic Acid

AbstractThe introduction of nanomaterials as modified electrode materials into the field of electrochemical sensing is expected to improve the reliability, sensitivity, selectivity and repeatability of electrochemical sensors in detecting pollutants in the water environment. In this study, copper vanadate nanomaterials (Cu3V2O7(OH)2·2H2O, referred to as CVO) and Cu3V2O7(OH)2·2H2O/polyyaniline (PANI) composite nanomaterials (referred to as CVO/PANI) were successfully prepared and characterized by Fourier transform infrared spectrum (FTIR), X‐ray traveling‐action (XRD), scanning electron microscopy (SEM) and high‐resolution transmission electron microscopy (HR‐TEM).The modified glassy carbon electrodes (GCE) with these two materials were used for the detection of benzoic acid (BA) and exhibited excellent electrochemical sensing performance. The results show that two pairs of semi‐reversible redox peaks exist in both CVO and CVO/PANI modified glassy carbon electrode (GCE) in BA solution. The linear range of CVO and CVO/PANI nanomaterials‐modified GCE was 0.01‐2 mM and 0.001‐2 mM, and the limits of detection were 2.16 µM and 0.41 µM, respectively. Polyaniline plays important role in the electrochemical responses of BA at CVO/PANI modified GCE. PANI enhancedthe intensities of CV peaks and electrochemical determination ability for BA.This article is protected by copyright. All rights reserved

LDH-Based Voltammetric Sensors

Layered double hydroxides (LDHs), also named hydrotalcite-like compounds, are anionic clays with a lamellar structure which have been extensively used in the last two decades as electrode modifiers for the design of electrochemical sensors. These materials can be classified into LDHs containing or not containing redox-active centers. In the former case, a transition metal cation undergoing a reversible redox reaction within a proper potential window is present in the layers, and, therefore, it can act as electron transfer mediator, and electrocatalyze the oxidation of an analyte for which the required overpotential is too high. In the latter case, a negatively charged species acting as a redox mediator can be introduced into the interlayer spaces after exchanging the anion coming from the synthesis, and, again, the material can display electrocatalytic properties. Alternatively, due to the large specific surface area of LDHs, molecules with electroactivity can be adsorbed on their surface. In this review, the most significant electroanalytical applications of LDHs as electrode modifiers for the development of voltammetric sensors are presented, grouping them based on the two types of materials.

Electrochemical Sensor Based on a MXene Nanosheet–Gold Nanourchin Hybrid as a Superoxide Dismutase Mimic for Real-Time Detection of Superoxide Anions Released from Living Cells

Electrochemical Sensor Based on a MXene Nanosheet–Gold Nanourchin Hybrid as a Superoxide Dismutase Mimic for Real-Time Detection of Superoxide Anions Released from Living Cells

Design and fabrication of an electrochemical sensor based on nanocomposite of dendritic polymer and reduced graphene oxide to measure sports nutrition lactate

Design and fabrication of an electrochemical sensor based on nanocomposite of dendritic polymer and reduced graphene oxide to measure sports nutrition lactate