Cyclic Voltammetry Techniques Research Articles

One-Step Electrochemical Synthesis of Molybdenum-Disulfide-Based Materials for Enhanced Supercapacitor Performance

Molybdenum disulfide (MoS2)-based two-dimensional materials were produced in one-step at room temperature using cyclic voltammetry technique. These materials were then used as electrode materials in supercapacitors. Concentration of supporting electrolyte, precursor, and cycle number parameters, which were the factors affecting the success of the synthesis, were optimized as 0.5 M, 0.15 M,and 10 cycles, respectively. The produced MoS2-coated electrodes were characterized using spectroscopic and microscopic methods. The chemical characterizations of the produced materials were examined by X-ray photoelectron spectroscopy, X-ray diffraction diffractometry, and scanning electron microscopy-energy-dispersive X-ray analysis. Surface morphologies of the composite materials were investigated using scanning electron microscopy. Finally, the produced MoS2-based materials were used as electrode materials in supercapacitors. The produced supercapacitors were characterized using cyclic voltammetry and electrochemical impedance spectroscopy methods, and the changes in the capacitive behavior of these systems over cycles were investigated using the cyclic charge-discharge technique. The highest areal capacitance value was determined as 251 mF.cm−2 at 0.2 mA.cm−2 charge-discharge current rates in 1.0 M H2SO4 by using of MoS-AD1 as the electrode material. Capacitance retention of this electrode was over 100% after 4000 cycles.

Cyclic and Square Wave Voltammetry Analysis of MTZ Using Reactive Electrode Based on Montmorillonite and Na-Alginate

This work describes the elaboration and the electroanalytical tests of a new electrode based on a mixture of graphite and biopolymer-modified montmorillonite nanocomposite. Initially, the nanocomposite was synthesized using sodic montmorillonite (NaMT) and sodium alginate (Naalg) extracted from Tunisian algae. The resulting nanocomposite was characterized by X-ray diffraction (XRD), infrared spectroscopy (UATR), and differential scanning calorimetry (DSC). XRD analysis revealed an increase in the basal spacing d001 and the appearance of reflections (020) and (220) of guluronan groups. Infrared spectra showed characteristic polymer bands such as symmetric and antisymmetric stretching vibrations of the carboxylic group in the nanocomposite spectra indicating the modification. Thermal analysis displayed a shift in the temperature of Naalg decomposition to a higher temperature in the nanocomposite thermogram.The obtained nanocomposite was then used in the development of an electrode. The resulting hybrid electrode was tested for metronidazole (MTZ) analysis using cyclic voltammetry (CV) and square wave voltammetry (SWV). Various parameters including pH, scan rate, MTZ concentration, frequency, etc., were investigated. The results revealed the irreversibility of the studied molecule and indicated that the reduction mechanism involves both diffusion and adsorption behaviors. SWV showed a better sensitivity to detect MTZ than the CV technique. Promising results were obtained, suggesting prospects for this new hybrid electrode.

Examining the dual effect of copper nanoparticles and nitrogen doping on Cu@N-TiO2

Abstract The study of six compositions of Cu@N-TiO2 with different amounts of copper and nitrogen synthesized using a sol–gel method is reported. X-ray diffraction patterns and Raman spectra indicated the formation of a single anatase TiO2 phase in all materials without evidence of secondary phases including copper or nitrogen. Electron microscopy images showed a homogeneous distribution of the copper particles around a TiO2 matrix, just as that the insertion of nitrogen did not have a significant effect on the morphology of the particles. X-ray photoelectron spectroscopy analysis confirmed that nitrogen was inserted in the atomic arrangement of titanium dioxide, while copper was presented mainly as metallic element on the TiO2 surface. Characterization of the optical properties and photoactivity test confirm that band gap strongly depends on the copper and nitrogen content phenomenon attributed to the combined presence of modifiers over the TiO2 surface and the promotion of a plasmonic effect, which displaced the absorption UV bands to higher wavelengths with respect to un-doped TiO2. The catalytic test performed using rhodamine-B as probe molecule, confirm that TiCuN2 and TiCuN3 samples exhibit the best decomposition percentages of 38 and 36 % respectively. Such results confirm the surface plasmon resonance effect associated to Cu particles on the TiO2 as main cause in the increase in current along synthesized samples and the use of cyclic voltammetry technique to identify these effects between 0.0 and 1.5 V.

Monitoring the Behavior of Na Ions and Solid Electrolyte Interphase Formation at an Aluminum/Ionic Liquid Electrode/Electrolyte Interface via Operando Electrochemical X-ray Photoelectron Spectroscopy.

In electrochemical energy storage devices, the interface between the electrode and the electrolyte plays a crucial role. A solid electrolyte interphase (SEI) is formed on the electrode surface due to spontaneous decomposition of the electrolyte, which in turn controls the dynamics of ion migration during charge and discharge cycles. However, the dynamic nature of the SEI means that its chemical structure evolves over time and as a function of the applied bias; thus, a true operando study is extremely valuable. X-ray photoelectron spectroscopy (XPS) is a widely used technique to understand the surface electronic and chemical properties, but the use of ultrahigh vacuum in standard instruments is a major hurdle for their utilization in measuring wet electrochemical processes. Herein, we introduce a 3-electrode electrochemical cell to probe the behavior of Na ions and the formation of SEI at the interface of an ionic liquid (IL) electrolyte and an aluminum electrode under operando conditions. A system containing 0.5 molar NaTFSI dissolved in the IL [BMIM][TFSI] was investigated using an Al working electrode and Pt counter and reference electrodes. By optimizing the scan rate of both XPS and cyclic voltammetry (CV) techniques, we captured the formation and evolution of SEI chemistry using real-time spectra acquisition techniques. A CV scan rate of 2 mVs-1 was coupled with XPS snapshot spectra collected at 10 s per core level. The technique demonstrated here provides a platform for the chemical analysis of materials beyond batteries.

Simultaneous analysis of chloramphenicol, amoxicillin, and enrofloxacin using electrochemical sensors with multilayer graphene electrodes fabricated by electrochemical methods in an organic solvent

In this study, three antibiotics, chloramphenicol (CAP), amoxicillin (AMX), and enrofloxacin (ENR), were simultaneously analysed for the first time using electrochemical sensors. The multilayer graphene electrode used in the sensor was directly and rapidly fabricated from graphite through a one-step chronoamperometry method. Scanning electron microscopy and cyclic voltammetry techniques revealed the multilayer-graphene nanostructure of the prepared electrode with a large electrochemically active surface area and good electrochemical activity. The electrode exhibited the best electrochemical oxidation signals corresponding to the three antibiotics when fabricated at a potential of 5 V for 20 s. Under optimised conditions, the sensor demonstrated excellent multi-analyte analysis capability, with clear separation and good linearity of the signals of the three antibiotics (R2>0.99) in relation to their concentrations. The sensor exhibited high accuracy and sensitivity with detection limits of 0.060, 0.381, and 0.109 μM for CAP, AMX, and ENR, respectively. The applicability of the sensor was demonstrated through acceptable recoveries of all three antibiotics when simultaneously analysed in a lake water sample.

Sensitive detection of cardiac glycoside digoxin based on sheet like structured cerium manganese oxide electrocatalyst

Digoxin (DGN), a widely used cardiac glycoside steroid for treating heart diseases. The prescription dosage range of digoxin is 0.5 – 2.0 ng/mL and concentration above 2 ng/mL can lead to intoxication. To monitor and detect digoxin in blood level is essential to minimize the endanger toxicity of human health. Addressing this concern, here we prepare a cerium manganese oxide (CMO) catalyst by a simple chemical coprecipitation method followed by heat treatment. The CMO morphological and structural characteristics were investigated by various spectroscopic techniques. The electrochemical properties of CMO catalyst were evaluated using cyclic voltammetry (CV) and differential pulse voltammetry (DPV) techniques, which also determined its electrochemical performance. Due to the high conductivity and large surface area with abundant active sites, CMO catalyst was used as a modified electrode material for detecting DGN in biological samples. The CMO sensor exhibits excellent electrocatalytic performance, with a dynamic linear range of 7.81 ×10–6 pg/L to 430 ×10–6 pg/L. The limit of detection and limit of quantification (LOD and LOQ) were found to be 1.99 ×10–6 pg/L and 6.05 ×10–6 pg/L, respectively. Furthermore, the sensor’s efficiency was validated through selectivity test and analysis of biological samples such as human blood and urine.

Tether-directed regioselective synthesis of new cis-2ʹ azafullerene bisadducts

Embarking into unexplored realms beyond the C1equatorial-face and C1trans-4′ regioisomers, this study delves into the synthesis of cis-2ʹ C59N bisadducts. The synthesis involves a two-step process. Firstly, a Mannich-type reaction between bisazafullerene (C59N)2 and a tether yields a monoadduct. Further Bingel-Hirsch cyclopropanation results in the formation of the desired cis-2ʹ C59N bisadducts. Comprehensive spectroscopic techniques, including polarimetry and X-ray crystallography, confirm the absolute configuration (f,sclockwise or f,santiclockwise) of the enantiomerically pure cis-2ʹ C59N bisadducts. Circular dichroism measurements revealed the extremely high chiroptical activity of these inherently chiral bisadducts. Evaluation of their optoelectronic properties through Vis-NIR absorption, PL emission, and cyclic voltammetry techniques reveals distinctive bandgap and NIR emission, ranging from 1.31 to 1.81 eV and 700–1108 nm, respectively, showcasing promising potential for applications in energy conversion.

Synthesis, Electrochemical Studies and Theoretical Calculations of Sulfo‐Schiff Bases

AbstractIn this study, two different water‐soluble Schiff base ligands as sodium(Z)‐3((2,5‐dihydroxybenzylidene)amino)benzene sulfonate (SLI) ve sodium (Z)3‐((3,4‐dihydroxybenzylidene)amino)benzene sulfonate (SLII) were synthesized as a result of the condensation reaction of 3‐aminobenzenesulfonicacid containing sulfo group with 2,5‐dihydroxybenzaldehyde and 3,4‐dihydroxybenzaldehyde, respectively. The chemical structures of the synthesized Schiff base ligands were characterized by melting point determination, elemental analysis, FT‐IR and 1H‐NMR techniques. Electrochemical behaviors of synthesized SLI and SLII ligands were examined by cyclic voltammetry technique against Ag/AgCl/KCl(sat) at the glassy carbon electrode in Britton Robinson buffer solution, pH 5.0. Electrode surfaces modified with SLI and SLII ligands were characterized by cyclic voltammetry technique in the presence of ferrocene and potassium hexacyanoferrate (III) redox probes, water contact angle measurement, scanning electron microscope and atomic force microscope and compared with the data of the bare glassy carbon electrode surface. Theoretical calculations of SLI and SLII ligand were performed with Density Functional Theory (DFT) and compared with experimental results.

Electrochemical Determination of Anti‐Cancer Drug Dabrafenib with High Sensitivity Using Multi‐Walled Carbon Nano Tubes Modified Glassy Carbon Electrode

AbstractDabrafenib (DAB) is an organofluor compound and a protein kinase inhibitor used as the mesylate salt in the treatment of metastatic melanoma. For the first time, the electrochemical investigation of the anticancer drug DAB in human serum was conducted using a glassy carbon electrode modified with multi‐walled carbon nanotubes (MWCNTs), employing cyclic voltammetry and square wave voltammetry (SWV) techniques. Electrochemical impedance spectroscopy, cyclic voltammetry, and scanning electron microscopy (SEM) techniques were utilized to analyze the surface morphology and structure of the MWCNT/GC electrode. In the proposed method using optimized experimental conditions, two different linearities were obtained for DAB in the concentration range of 0.04–0.8 μM and 1.0–10.0 μM. The LOD value obtained is 0.014 μM. In this study, the resulting electrochemical sensor was applied for the first time to investigate the electrochemical behavior of DAB with high sensitivity and reproducibility, as well as the possible electrochemical oxidation mechanism.

Nanofiber enhanced carbon cloth based flexible Miniaturized electrodes for Real-Time and specific insulin detection in blood serum

The development of sensitive and specific biosensors for real-time insulin monitoring is crucial for advancing diabetes management and improving patient outcomes. This study reports the fabrication of flexible electrodes based on titanium dioxide (TiO2) nanofiber-enhanced carbon cloth (CC) for the real-time, selective picomolar range of detection of insulin in blood serum. TiO2 nanofibers significantly increase the electrodes surface area and electron transfer capabilities, enhancing sensitivity and enabling rapid response times essential for real-time monitoring. The flexibility and mechanical stability of the carbon cloth substrate make it ideal for wearable and implantable biosensors, addressing limitations of conventional sensors, such as inadequate sensitivity, delayed response times, rigidity, and non-specific binding. The enhanced properties of the TiO2 nanofiber-modified carbon cloth composite facilitate the detection of low insulin concentrations, essential for early diagnosis and continuous monitoring in diabetes care. The robust TiO2 nanofibers and durable carbon cloth ensure sustained performance in complex biological environments. Chronoamperometry (CA) and cyclic voltammetry (CV) techniques are used to examine the electrocatalytic activity of the fabricated sensor, assessing parameters like pH, electrode resistance, concentration, and scan rate. While fasting, the normal range of insulin ranges from 12 to 150 pM. This sensor detects insulin in the 7 pM to 1000 pM range, with a detection limit of 2.7 pM and a quantification limit of 8.7 pM. Portability is validated using a handheld smartphone-based potentiostat. This developed miniaturized sensor provides a selective, interference-mitigated response for insulin detection in human serum, demonstrating significant advancements in flexible electrochemical sensor technology with crucial implications for diabetes care.

Comprehensive analysis of Alpelisib detection: Uniting molecular docking, dynamics, and precision electrochemistry at the PEDOT:PSS-carbon paste interface

The increasing utilization of carbon paste electrodes (CPE) in developing electrochemical sensors has led to a heightened search for innovative electrode materials. In the present study, incorporating poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonate) (PEDOT:PSS) emerges as a pivotal modification technique for the electrochemical determination of Alpelisib (ALP), a paramount anticancer agent. The electrochemical behavior of ALP at the interface of the PEDOT:PSS-modified CPE was thoroughly investigated using differential pulse voltammetry (DPV) and cyclic voltammetry (CV) techniques. By capitalizing on the intrinsic electrocatalytic properties of PEDOT:PSS, a refined design of a CPE was developed, enabling the electrochemical detection of ALP with enhanced sensitivity. The oxidation peak currents attributed to ALP exhibited a linear increase within the concentration range of 0.01–5 μM, and the detection limits were determined to be 4.8 nM. Significantly, this study highlights the effective utilization of the PEDOT:PSS-modified CPE for the electrochemical analysis of ALP in various matrices, including urine, human plasma, and pharmaceutical samples. Crucially, molecular docking and dynamics simulations substantiate the binding efficacy of ALP and its metabolites to the target protein, further corroborating the sensor’s precision in diverse biological and pharmaceutical mediums. The achieved recovery rates demonstrate the strength and effectiveness of the applied system. In addition to expanding the field of electrochemical sensor development, this study presents a robust framework for accurately measuring ALP, which has important implications in both clinical and pharmaceutical contexts.

Ultra-high sensitivity pH sensor based on vertical organic electrochemical transistors with extended gate.

Anultra-high sensitivity pH sensor based on vertical organic electrochemical transistors (vOECT) with extended gate was proposed. The vOECT, which exhibited high transconductance (gm), was forthe first time used in the preparation of apH sensor. The extended gate was modified by electrochemical deposition of polyaniline (PANI) using the cyclic voltammetry (CV) technique. Open circuit potential (OCP) measurements were used to optimize the scan rate, showing a super-Nernstian sensitivity at all scan rates. The pH sensor based on vOECT with extended gate was investigated at different pH levels, and it exhibited an ultra-high sensitivity of 3363.6 µA/pH in the pH range 5-9, which was about 36 times greater than the maximum current sensitivity (91 µA/pH) of other transistor-based pH sensors, to the best of our knowledge. This pH sensor performed excellently in terms of reversibility, long-term stability, and selectivity. To confirm the reliability of the pH sensor, we conducted measurements on real samples using this pH sensor and compared the results with those obtained from a standard pH meter. The ultra-high sensitivity pH sensor based on vOECT with extended gate offers a sensitive and promising alternative in environmental monitoring, food safety, chemistry, clinical diagnostics, and bio-sensing applications.

Heterojunction of branched benzopyrazine-based polymers coating on graphene for electrochemical sensing of vanillin

Vanillin finds widespread applications in various industries, such as food, pharmaceuticals, and cosmetics. However, excessive intake of vanillin could pose risks to human health. This study detailed the successful creation of a heterojunction of branched benzopyrazine-based polymers coating on graphene (CMP-rGO) through the Sonogashira-Hagihara coupling reaction. Utilizing the CMP-rGO, a novel electrochemical sensor for vanillin detection was developed. Besides, the synthesized materials were validated using standard characterization techniques. Both cyclic voltammetry and differential pulse voltammetry techniques were employed to investigate vanillin's electrochemical characteristics on this sensor. The findings indicated a significant enhancement in vanillin's electrochemical signal responsiveness with the application of CMP-rGO. Under optimal conditions, the sensor demonstrated a linear response to vanillin concentrations ranging from 0.08 to 33 μM and achieved a detection limit as low as 0.014 μM. Also, the constructed electrochemical sensor exhibited excellent selectivity, stability, and reproducibility. It has been effectively employed to detect vanillin in real samples such as human serum, human urine, and vanillin tablets, with a recovery rate of 99.13–103.6 % and an RSD of 3.46–1.26 %. Overall, this innovative sensor offers a novel approach to the efficient and convenient detection of vanillin.

Fabrication of Strontium Molybdate with Functionalized Carbon Nanotubes for Electrochemical Determination of Antipyretic Drug-Acetaminophen.

In recent years, there has been a significant interest in the advancement of electrochemical sensing platforms to detect antipyretic drugs with high sensitivity and selectivity. The electrochemical determination of acetaminophen (PCT) was studied with strontium molybdate with a functionalized carbon nanotube (SrMoO4@f-CNF) nanocomposite. The SrMoO4@f-CNF nanocomposite was produced by a facial hydrothermal followed by sonochemical treatment, resulting in a significant enhancement in the PCT determination. The sonochemical process was applied to incorporate SrMoO4 nanoparticles over f-CNF, enabling a network-like structure. Moreover, the produced SrMoO4@f-CNF composite structural, morphological, and spectroscopic properties were confirmed with XRD, TEM, and XPS characterizations. The synergistic effect between SrMoO4 and f-CNF contributes to the lowering of the charge transfer resistance (Rct=85 Ω·cm2), a redox potential of Epc=0.15 V and Epa=0.30 V (vs. Ag/AgCl), and a significant limit of detection (1.2 nM) with a wide response range of 0.01-28.48 µM towards the PCT determination. The proposed SrMoO4@f-CNF sensor was studied with differential pulse voltammetry (DPV) and cyclic voltammetry (CV) techniques and demonstrated remarkable electrochemical properties with a good recovery range in real-sample analysis.

Novel method of phosphorous doped bismuth oxide with carbon aerogel for a selective voltammetry quantification of anti-cancer drug: Regorafenib

Regorafenib (REG) is an oral multikinase inhibitor derived from diphenylureas. This drug is prescribed to treat colorectal and gastrointestinal stromal tumors and hepatocellular carcinoma. Our present study demonstrates the non-enzymatic electrochemical determination of REG in human blood serum at low concentrations by applying phosphorous-doped bismuth oxide (P-BiO) and porous graphene oxide (PGO)/protonated graphitic carbon nitride (PGCN) combined Aerogel form a P-BiO/Aerogel nanohybrids fabricated glassy carbon electrode (GCE). The property of our proposed electrocatalyst was characterized using several spectroscopic techniques. Utilizing cyclic voltammetry and differential pulse voltammetry techniques the electrochemical performance of this designed sensor was analyzed. Our P-BiO/Aerogel/GCE sensor exhibited a lower detection limit (LOD) of 0.1 nM with a high sensitivity of 1.433 µA µM-1cm−2. As a part of the real-time functionality, our fabricated sensor quantified the trace levels of REG in the consumed patient’s blood serum samples at the recovery range of 99–103 %. Therefore, our P-BiO/Aerogel nanohybrid electrocatalyst is a promising electrocatalyst for the real-time monitoring of REG.

Molecular-Imprinting Assisted Polydopamine-Aptasensor On Carbon and Gold Nanomaterials Construct for The Haemophilia B Biomarker Detection

The study presents a comprehensive approach for enhancing the performance of a spiral micro-interdigitated electrode (spiral-μIDE) sensor for the detection of FIX protein. Electropolymerization using dopamine resulted in a molecular-imprinted polymer (polyDOP-μIDE-MIP) layer, which encapsulated the aptamer-FIX complex and was later leached to create cavities. Cyclic and linear-sweep voltammetry techniques were utilized for the MIP development and rebinding assessment. Linear sweep voltammetry demonstrated a linear relationship between FIX concentration and peak current reduction, with a limit of detection (LOD) of 0.250 picomolar. The sensor's sensitivity was determined as 2.613E-10 A.fM-1.μm-2. This work highlights the importance of nanomaterials integration, and electropolymerization in improving sensor performance. The integration of carbon and gold nanomaterials and the use of molecular imprinting contribute to the sensor's enhanced sensitivity and selective detection of FIX protein.

Effect of Bi doping on the electrochemical behaviour of Mg2SiO4 nanoparticle for energy storage applications

Silicate-based compounds are promising nanomaterials due to their high specific surface area, thermal stability, chemical stability, and fast kinetics. In this study, we synthesised pure, 2% Bi-doped, and 4% Bi-doped Mg2SiO4 nanoparticles using a simple and cost-effective sol-gel method. Various techniques such as XRD, FESEM, EDAX, FTIR, Raman, UV-Vis-NIR, cyclic voltammetry (CV), and galvanostatic charge-discharge (GCD) were employed to investigate the prepared samples. XRD patterns confirmed the crystalline phases through phase matching; and the crystallite size, dislocation density, and residual strain were derived. FESEM images showed that pure and Bi-doped Mg2SiO4 have regular spherical shapes and uniform sizes with minimal agglomeration. Particle sizes determined from FESEM images were 49 nm for the pure sample, 42 nm for the 2% Bi-doped sample, and 40 nm for the 4% Bi-doped sample. FTIR and Raman spectra verified the presence of various vibrational modes characteristic of the Mg2SiO4 structure. The UV-Vis-NIR spectra indicated strong absorption in the ultraviolet region upon doping with bismuth. The impact of Bi doping on the electrochemical behaviour of Mg2SiO4 was studied using CV and GCD techniques in a three-electrode system, where the sample-coated Mg foil (active material/activated carbon/polypyrrole) served as the working electrode. GCD curves showed that the 4% Bi-doped Mg2SiO4 electrode exhibited a maximum specific capacitance of 1043 F/g, outperforming the pure and 2% Bi-doped samples. Additionally, the 4% Bi-doped electrode maintained a capacity retention of 80% over 400 cycles. These results suggest that 4% Bi-doped Mg2SiO4 nanoparticles are excellent candidates for electrode material in energy storage applications.

Ag nanoparticles incorporated metal organic framework (Ag@ZnBDC): Highly sensitive and selective detection of Hg2+ ions

Heavy metal ions (HMIs) pollutants pose remarkable hazards to humans and the environment. Their toxicity is a concern for both aquatic life and humans. HMIs directly threaten humans when consumed through drinking water or aquatic species such as fish. Therefore, detecting, quantifying, and removing these pollutants from water sources is necessary. In this study, we fabricated a highly selective and sensitive Hg2+ ion electrochemical sensor using a solvothermally synthesized composite of silver nanoparticles (Ag NPs) and zinc benzene dicarboxylate (ZnBDC) (Ag@ZnBDC) metal–organic framework (MOF) at trace levels. The synthesized Ag@ZnBDC MOFs composite was studied using various characterization techniques: structural, spectroscopic, thermal, Brunauer-Emmett-Teller surface area, morphological, elemental, and electrochemical techniques. The electrochemical sensor was fabricated by drop-casting the Ag@ZnBDC composite onto a glassy carbon electrode, and its sensing properties were evaluated using cyclic voltammetry and differential pulse voltammetry techniques. Remarkably, the sensor exclusively and highly selectively responded to Hg2+ ions among Cd2+, Cr3+, Cu2+, Fe3+, and Pb2+ ions at a concentration of 1 μM. The Ag@ZnBDC sensor showed a limit of detection of 4.16 nM in the linear response within the concentration range of 1–10 nM for Hg2+ ions.

4-Ethylphenyl Sulfate Detection by an Electrochemical Sensor Based on a MoS2 Nanosheet-Modified Molecularly Imprinted Biopolymer.

One of the gut-derived uremic toxins 4-ethylphenyl sulfate (4-EPS) exhibits significantly elevated plasma levels in chronic kidney diseases and autism, and its early quantification in bodily fluids is important. Therefore, the development of rapid and sensitive technologies for 4-EPS detection is of significant importance for clinical diagnosis. In the current work, the synthesis of a molecularly imprinted biopolymer (MIBP) carrying 4-EPS specific cavities only using the biopolymer polydopamine (PDA) and molybdenum disulfide (MoS2) nanosheets has been reported. The fabricated electrode was prepared using screen-printed carbon electrodes on a polyvinyl chloride substrate. The synthesized material was characterized using several techniques, and electrochemical studies were performed using cyclic voltammetry (CV) and differential pulse voltammetry (DPV) techniques. The DPV technique for the electrochemical sensing of 4-EPS using the fabricated sensor (PDA@MoS2-MIBP) determined a sensitivity of 0.012 μA/ng mL/cm2 and a limit of detection of 30 ng/mL in a broad linear range of 1-2200 ng/mL. Also, the interferent study was performed to evaluate the selectivity of the fabricated sensor along with the control and stability study. Moreover, the performance of the sensor was evaluated in the spiked urine sample, and a comparison was made with the data obtained by ultraperformance liquid chromatography-tandem mass spectroscopy.

Spectroscopic and antibacterial activities of cobalt and nickel nanoparticles: a comparative analysis

This study aimed to compare the spectroscopy, morphological, electrocatalytic properties, and antibacterial activities of cobalt nanoparticles (CoNPs) with nickel nanoparticles (NiNPs). Cobalt nanoparticles and NiNPs were prepared via a chemical reduction approach and characterized utilizing transmission electron microscopy (TEM), energy-dispersive X-ray (EDX), and X-ray diffraction (XRD) techniques. The result from XRD and TEM analysis revealed that the synthesized nanoparticles exhibit face-centered cubic with smooth spherical shape, having average particles size of 12 nm (NiNPs) and 18 nm (CoNPs). The electrochemical properties of the nanoparticles were examined via cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) techniques. The CV results showed that GCE-Ni (35.6 μA) has a higher current response compared to GCE-Co (10.5 μA). The EIS analysis revealed that GCE-Ni (1.39 KΩ) has faster electron transport capability compared to GCE-Co (2.99 KΩ) as indicated in their Rct values. The power density of the synthesized nanoparticles was obtained from their "knee" frequency (f°) values, with GCE-Ni (3.16 Hz) having higher f° values compared to GCE-Co (2.00 Hz). The antibacterial activity of the nanoparticles was evaluated against multidrug-resistant Escherichia coli O157, Escherichia coli O177, Salmonella enterica, Staphylococcus aureus, and Vibrio cholerae. The result from the antibacterial study revealed that at low concentrations both CoNPs and NiNPs have significant antibacterial activities against E. coli O157, E. coli O177, S. enterica, S. aureus, and V. cholerae. NiNPs showed better antibacterial activities at low concentrations of 61.5, 61.5, 125, 61.5, and 125 µg/mL compared to CoNPs with minimum inhibitory concentrations of 125, 125, 250, 61.5, and 125 µg/mL against E. coli O157, E. coli O177, S. enterica, S. aureus, and V. cholerae, respectively. These promising antibacterial activities emphasize the potential of CoNPs and NiNPs as effective antibacterial agents, which could aid in the development of novel antibacterial medicines.