Glass Carbon Electrode Research Articles

Development of a magnetic α-Fe2O3/Fe3O4 heterogeneous nanorod-based electrochemical biosensing platform for HPV16 E7 oncoprotein detection

The prevention, diagnosis and treatment of cancer have always been the focus of medical research. In this study, a label-free, rapid, simple, sensitive, and specific method for the detection of HPV16 E7 oncoprotein was developed. The electrochemical biosensor platform was constructed by magnetic self-assembly of α-Fe2O3/Fe3O4@Au nanocomposites onto the surface of magnetic glass carbon electrode (MGCE), and the nanocomposite was connected to aptamer through AuS bond to construct a probe to capture HPV16 E7. Cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) were applied to verify the performance of the constructed biosensor. The condition optimization and performance analysis were carried out by differential pulse voltammetry (DPV). Under optimal conditions, the biosensor exhibited a strong linearity between current value and the logarithm of HPV16 E7 oncoprotein concentration in the range of 10 pg/mL – 0.1 μg/mL, with a limit of detection (LOD) of 159 fg/mL and a limit of quantification (LOQ) of 530 fg/mL, and it also revealed excellent reproducibility, long-term stability, and anti-interference ability. In a word, the biosensor would contribute to the early diagnosis of oncoprotein HPV16 E7 and had promising application prospects.

Novel Zn-based metal coordination polymer for ultrafast capture and electrochemical sensing of Hg(Ⅱ)

The electrochemical sensor shows great promise in the detection of trace Hg(Ⅱ), of which the performance could be significantly enhanced by the functionalized material with the merits of effective and ultrafast capture for Hg(Ⅱ). In this study, the novel metal coordination polymers (MCPs) was synthesized by the 2-thio-barbituric acid as the organic ligand to modify the electrochemical sensor to address this issue. The as-prepared material was composed of regular flakes with a polyhedral and well-defined crystal structure, the successful loading of the abundant sulfurous group (7.49 % of the total mass) endowed the Zn-TBA with the capability to efficiently uptake (97.4–99.9 %) Hg(Ⅱ) at 500 mg/L under a wider pHs as well as the high content of coexisting cations and anions, highlighted the excellent capacity, strong environmental adaptability, and selectivity. Notably, the superfast mass transfer was revealed in the adsorption kinetics test, in which the Hg(Ⅱ) content was effectively reduced from 50 mg/L to 14 μg/L within 20 s to meet the national emission standards. Based on this, Zn-TBA modified the carbon cloth (Zn-TBA/CC) and the glass carbon electrode (Zn-TBA/GCE) was prepared, thereinto, the current response of Zn-TBA/CC was approximately 60 times that of the pristine electrode. A strong positive correlation (R2=0.998) relationship could be attained across the content of 0.25–3 μM, achieving the detection limit to be 0.29 μM. The impressive performance was maintained in the complex matrices and regeneration test. In addition, Zn-TBA/CC exhibited better physical properties, charge transfer ability, and sensing properties than Zn-TBA/GCE, highlighting the advantages of CC as a flexible sensor substrate. Finally, the stable recovery (90–98.5 %) in the spiked actual surface water confirmed that the two established methods possessed a promising application potential in capturing and detecting the trace Hg(Ⅱ) with high accuracy and precision. This study extended the application of MCPs in the electrochemical sensor and provided an available analysis method to trap and determine the metal content.

Multicolor Electrochemiluminescence of Binary Microcrystals of Iridium and Ruthenium Complexes.

We here report the multicolor electrochemiluminescence (ECL) of binary microcrystals prepared from a blue-emissive iridium complex 1 and an orange-emissive ruthenium complex 2. These materials display a plate-like morphology with high crystallinity, as demonstrated by microscopic and powder X-ray diffraction analyses. Under light excitation, these microcrystals exhibit gradient emission color changes as a result of the efficient energy transfer between two complexes. When modified on glass carbon electrodes, these microcrystals exhibit tunable ECLs with varied emission colors including sky-blue, white, orange, and red, depending on the doping ratio of complex 2 and the applied potential. Furthermore, organic amines with different molecular sizes are used as the co-reactant to examine their influences on the ECL efficiency of the porous microcrystals of 1. The analysis on the luminance and RGB values of ECL suggests the existence of energy transfer in the generation of multicolor ECLs in these binary crystals.

Detection of Tert-Butylhydroquinone in Edible Oils Using an Electrochemical Sensor Based on a Nickel-Aluminum Layered Double Hydroxide@Carbon Spheres-Derived Carbon Composite.

Phenolic antioxidants such as tert-butylhydroquinone (TBHQ) can prolong the shelf life of edible oils by delaying the oxidation process. The excessive use of TBHQ can damage food quality and public health, so it is necessary to develop an efficient TBHQ detection technique. In this work, nickel-aluminum double hydroxide (NiAl-LDH) was grown on glucose carbon spheres (GC), which formed porous carbon nanomaterials (named NiAl-LDH@GC-800) after pyrolysis at 800 °C. The successful synthesis of the material was verified by scanning electron microscopy, X-ray diffraction, and X-ray photoelectron spectroscopy. The obtained NiAl-LDH@GC-800 was dopped onto a glass carbon electrode to prepare an electrochemical sensor for TBHQ. The synergistic effect of porous carbon and Ni metal reduced from NiAl-LDH by high-temperature calcination accelerated the electron transfer rate and improved the sensitivity of the sensor. The prepared sensor showed a low limit of detection (LOD) of 8.2 nM, a high sensitivity (4.2 A·M-1), and a good linear range (20~300 µM) in detecting TBHQ. The sensor was also successfully used for TBHQ detection in edible oils, including chili oil, peanut oil, and rapeseed oil.

Highly efficient electrochemiluminescent properties of porphyrin-based metal-organic framework Zn-TCPP and its immunoassay application to the detection of ochratoxin A

BackgroundOchratoxin A (OTA) is a group of mycotoxins that are widely distributed in food and feed and are closely associated with human health, so it is particularly important to detect OTA in cereal-based foods. Porphyrins and their derivatives have been widely investigated for their excellent electrochemical luminescence properties. Tetrakis 4-carboxyphenyl) porphyrin (TCPP) has limited applications because of its tendency to aggregate in water. ResultsTo enhance the luminescence efficiency of TCPP, the porphyrin can be immobilized as an organic ligand in a metal-organic framework. This allows the preparation of a novel zinc-porphyrin-based MOF (Zn-TCPP nanorods), which in turn provides highly efficient and stable cathodic ECL signals. Herein, an ultra-sensitive electrochemiluminescence immunoassay was proposed using Zn-TCPP nanorods as high-efficiency luminophores and Bi2S3@Au nanoflowers as electrode substrate materials for the detection of ochratoxin A in foodstuffs. Zn-TCPP has a strong and stable signal, and has been used as an immunosensor probe material. The Bi2S3@Au nanoflowers was used to decorate the glass carbon electrode and support for antibody immobilization due to its good electrical conductivity and large specific surface area. Under the optimized conditions, the constructed immunosensor could realize the sensitive detection of ochratoxin A in the detection range of 0.0004 ng mL−1 to 500 ng mL−1 with the detection limit as low as 0.13 pg mL−1. In addition, the sensing platform has been used for the detection of OTA in wheat flour and feed. SignificanceHence, it is worth believing that this strategy can pave a bright research direction for the detection of ochratoxin A or other small molecule mycotoxins content in foods, as well as contributing to the further study of MOF in the field of ECL.

Highthroughput Screening of CuBi Bimetallic Catalyst Array for Electrocatalytic CO2 Reduction Reaction by Scanning Electrochemical Microscope.

The testing and evaluation of catalysts in CO2 electroreduction is a very tedious process. To study the catalytic system of CO2 reduction more quickly and efficiently, it is necessary to establish a method that can detect multiple catalysts at the same time. Herein, a series of CuBi bimetallic catalysts have been successfully prepared on a single glass carbon electrode by a scanning micropieptte contact method. The application of scanning electrochemical microscopy (SECM) enabled the visualization of the CO2 reduction activity in diverse catalyst micro-points. The SECM imaging with Substrate generation/tip collection (SG/TC) mode was conducted on CuBi bimetallic micro-points, revealing that HER reaction emerged as the prevailing reaction when a low overpotential was employed. While the applied potential was lower than -1.5 V vs. Ag/AgCl, the reduction of CO2 to formic acid became dominant. Increasing the bismuth proportion in the bimetallic catalyst can inhibit the hydrogen evolution reaction at low potential and enhances the selectivity of the CO product at high cathode overpotential. This research offers a novel approach to examining arrays of catalysts for CO2 reduction.

Construction of Co-MOF electrochemical sensor and application of it in recognizing and distinguishing naphthylamine isomers

A 3D Co-MOF:[Co(μ2-O)(L)4]n (Co-1, HL= nicotinic acid) was synthesized hydrothermal method. Co-1 was used as electrode materials modified onto a glass carbon electrode(GCE) to assemble Co-1/GCE. It served as an electrochemical sensor for recognizing and distinguishing aromatic amines isomer 1-naphthylamine(1-NA) and 2-naphthylamine(2-NA). The recognition potentials of 1-NAand 2-NA were 0.84 V and 0.74 V with the limits of detection (LOD) 1.025 μM and 0.875 μM, respectively, Furthermore, Co-1/GCE has high selectivity and excellent sensitivity towards 1-NAand 2-NAin mimic waste organic environment. An outstanding recognition and distinguish ability can be observed.

The synergistic effect of MnSe2/pyridine diketopyrrolopyrrole-grafted graphene oxide composite for sensitivity electrochemical detection of 4-nitrochlorobenzene

In view of the hazards and degradation inertia of 4-nitrochlorobenzene (4-NCB), it is very important to detect the content of 4-NCB in water samples. Here, we developed a simple platform to accurately monitor the content of 4-NCB based on MnSe2/pyridine diketopyrrolopyrrole-grafted graphene oxide nanocomposite (MnSe2/PDPP-rGO) constructed glass carbon electrode (GCE) sensor. MnSe2/PDPP-rGO composited has been synthesized by two-step hydrothermal method, and MnSe2 nanoclusters composed of nanorods grows uniformly on the surface of PDPP-rGO lamella. Combined with electrochemical activity of MnSe2 to 4-NCB and the excellent conductivity of PDPP-rGO which have been confirmed by cyclic voltammetry and electrochemical impedance spectroscopy, the as-prepared MnSe2/PDPP-rGO/GCE displays outstanding electrochemical sensing comprehensive performance to 4-NCB with wide linear range of 0.05–280 μM, low limit of detection of 4.8 nM, long stability for up to 20 days, satisfactory interference and repeatability. These results provide sufficient basis for accurate and practical detection of 4-NCB based on MnSe2/PDPP-rGO/GCE platform.

Novel Carbon-Coated Zirconium (IV) Oxide Nanocomposite for the Electrochemical Determination of Rutin

ZrO2 coated highly porous biomass carbon nanocomposites (ZrO2@KHPC) were synthesized by calcination. The ZrO2 was derived from an amino-functionalized metal-organic framework and the porous biomass carbon material was derived from waste sunflower products. A selective electrochemical sensor was fabricated by modifying glass carbon electrodes (GCE) using ZrO2@KHPC to determine rutin. KHPC with a porous structure exhibited strong adsorption, high specific surface area, and superior electrical conductivity, whereas ZrO2 nanoparticles with an octahedral crystal structure and high electrocatalytic activity promote the specific recognition of rutin. The ZrO2@KHPC/GCE sensor demonstrated exceptional performance with a low detection limit of 0.008 µM and a sensitivity of 28.45 µA·µΜ−1·cm−2 from 0.01 to 40 µM. This excellent performance is attributed to the synergistic combination of ZrO2 and KHPC. In addition, the electrochemical sensor demonstrated suitable stability, good selectivity, high reproducibility, and satisfactory recovery for practical analysis.

Controllable synthesis of cross-linked 3D ZnO nanosheet toward a nitrite electrochemical sensor

A 3D cross-linked ZnO (cl-ZnO) nanosheets were prepared via a simple one-pot hydrothermal approach, and then characterized by a series of modern advanced technique including XRD, SEM, TEM and XPS. This nanomaterial was used to modify the glass carbon electrode (GCE), obtaining an electrochemical sensor (cl-ZnO/GCE) of which the electrochemical properties were studied using various electrochemical techniques such as cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). The sensor exhibited remarkably enhanced electrocatalytic activity for nitrite ions (NO2-) in comparison to that of the commercially available ZnO-modified GCE. Two electrochemical techniques, including chronoamperometry (CA) and linear sweep voltammetry (LSV) were adopted to test the determination performance of the sensor for nitrite, it exhibited a good linear relationship within the range of 0.8 μmol·L-1 - 0.462 mmol·L-1 and 0.608 - 7.84 mmol·L-1 evaluated by CA, the limit of detection (LOD) and sensitivity for NO2- were 0.26 μmol·L-1 (S/N = 3) and 824.6 µA (mmol·L-1)-1cm-2, respectively. For LSV, the two linearity responses of 0.95 μmol·L-1- 0.515 mmol·L-1 and 0.667 mmol·L-1- 5.41 mmol·L-1, high sensitivity of 1336.1 µA (mmol·L-1)-1cm-2 with low LOD of 0.32 μmol·L-1 were gained. This sensor can be employed to detect trace amount of NO2- in ham sausage and pickled vegetables successfully, supporting an insight and strategy for more sensitive nitrite electrochemical sensor.

A novel ratiometric electrochemical sensing platform combined with molecularly imprinted polymer and Fe-MOF-NH2/CNTs-NH2/MXene composite for efficient detection of ofloxacin

BackgroundOfloxacin (OFL) is often abused in medicine and animal husbandry, which poses a great threat to human health and ecological environment. Therefore, it is necessary to establish efficient method to detect OFL. Electrochemical sensor has attracted widespread attention due to the advantages of low cost and fast response. However, most electrochemical sensors usually use one response signal to detect the target, which makes it sensitive to the variable background noise in the complex environment, resulting in low robustness and selectivity. The ratio detection mode and employing molecularly imprinted polymer (MIP) are two strategies to solve these problems. ResultsA novel molecular imprinting polymer-ratiometric electrochemical sensor (MIP-RECS) based on Fe-MOF-NH2/CNTs-NH2/MXene composite was prepared for the rapid and sensitive detection of OFL. The positively charged Fe-MOF-NH2 and CNTs-NH2 as interlayer spacers were introduced into the negatively charged MXene through a simple electrostatic self-assembly technique, which effectively prevented the agglomeration of MXene and increased the electrocatalytic activity. A glass carbon electrode was modified by the composite and a MIP film was electropolymerized on it using o-phenylenediamine and β-cyclodextrin as bifunctional monomers and OFL as template. Then a MIP-RECS was designed by adding dopamine (DA) into the electrolyte solution as internal reference, and OFL was quantified by the response current ratio of OFL to DA. The current ratio and the concentration of OFL displayed a satisfying linear relationship in the range of 0.1 μM–100 μM, with a limit of detection (LOD) of 13.2 nM. SignificanceCombining molecular imprinting strategy and ratio strategy, the MIP-RECS has impressive selectivity compared with the non-imprinted polymer-RECS, and has better repeatability and reproducibility than non-ratiometric sensor. The MIP-RECS has high sensitivity and accuracy, which was applied for the detection of OFL in four different brands of milk and was verified by HPLC method with satisfactory results.

Development and Characterization of a Sol-Gel-Functionalized Glass Carbon Electrode Probe for Sensing Ultra-Trace Amounts of NH3 and NH4+ in Water.

This study centers on the development and characterization of an innovative electrochemical sensing probe composed of a sensing mesoporous functional sol-gel coating integrated onto a glassy carbon electrode (sol-gel/GCE) for the detection of NH3 and/or NH4+ in water. The main interest for integrating a functional sol-gel coating onto a GCE is to increase the selective and sensing properties of the GCE probe towards NH3 and/or NH4+ ions. The structure and surface morphology of the newly developed sol-gel/GCE probe were characterized employing scanning electron microscopy (SEM), atomic force microscopy (AFM), dynamic light scattering (DLS), and Fourier-transform infrared (FTIR), while the electrochemical sensing properties were evaluated by Berthelot's reaction, cyclic voltammetry (CV), and adsorptive square wave-anodic striping voltammetry (Ads SW-ASV). It is shown that the newly developed sol-gel coating is homogeneously deposited on the GCE with a sub-micron and uniform thickness close to 630 nm and a surface roughness of 25 nm. The sensing testing of the sol-gel/GCE probe showed limits of detection and limits of quantitation of 1.7 and 5.56 nM of NH4+, respectively, as well as a probe sensitivity of 5.74 × 10-1 μA/μM cm-2. The developed probe was fruitfully validated for the selective detection of NH3/NH4+ in fresh and sea water samples. Computed Student texp (0.45-1.25) and Fexp (1.69-1.78) (n = 5) tests were less than the theoretical ttab (2.78) and Ftab (6.39) at 95% probability.

A Novel Electrochemical Sensor Based on Pd Confined Mesoporous Carbon Hollow Nanospheres for the Sensitive Detection of Ascorbic Acid, Dopamine, and Uric Acid.

In this study, we designed a novel electrochemical sensor by modifying a glass carbon electrode (GCE) with Pd confined mesoporous carbon hollow nanospheres (Pd/MCHS) for the simultaneous detection of ascorbic acid (AA), dopamine (DA), and uric acid (UA). The structure and morphological characteristics of the Pd/MCHS nanocomposite and the Pd/MCHS/GCE sensor are comprehensively examined using SEM, TEM, XRD and EDX. The electrochemical properties of the prepared sensor are investigated through CV and DPV, which reveal three resolved oxidation peaks for AA, DA, and UA, thereby verifying the simultaneous detection of the three analytes. Benefiting from its tailorable properties, the Pd/MCHS nanocomposite provides a large surface area, rapid electron transfer ability, good catalytic activity, and high conductivity with good electrochemical behavior for the determination of AA, DA, and UA. Under optimized conditions, the Pd/MCHS/GCE sensor exhibited a linear response in the concentration ranges of 300-9000, 2-50, and 20-500 µM for AA, DA, and UA, respectively. The corresponding limit of detection (LOD) values were determined to be 51.03, 0.14, and 4.96 µM, respectively. Moreover, the Pd/MCHS/GCE sensor demonstrated outstanding selectivity, reproducibility, and stability. The recovery percentages of AA, DA, and UA in real samples, including a vitamin C tablet, DA injection, and human urine, range from 99.8-110.9%, 99.04-100.45%, and 98.80-100.49%, respectively. Overall, the proposed sensor can serve as a useful reference for the construction of a high-performance electrochemical sensing platform.

Porous CePO4@carbon composite derived from cerium-based metal–organic framework for the simultaneous detection of dopamine, uric acid, and acetaminophen

Cerium phosphate (CePO4) has attracted increasing attention in the field of electrochemistry. In this work, a mesoporous CePO4@carbon composite was successfully prepared via the high-temperature calcination method using cerium-based metal–organic framework (Ce-MOF) as a precursor. The obtained samples were characterized by powder X-ray diffraction (PXRD), Fourier transform infrared spectroscopy (FT-IR), transmission electron microscopy (TEM), scanning electron microscopy (SEM), N2 adsorption–desorption technique, and X-ray photoelectron spectroscopy (XPS). The findings revealed that the in-situ pyrolysis of Ce-MOF generated uniform composite, which showed high electrical conductivity and plenty of catalytic active sites. These structural advantages of the composite were conductive to the electron transfer, substrate diffusion, and redox reactions. Thereafter, CePO4@carbon was developed to modify the commercially purchased glass carbon electrode (GCE: CHI 104) for simultaneous detection of dopamine (DA), uric acid (UA), and acetaminophen (APAP). The linear detection ranges for DA, UA, and APAP were 2.5–310.0 μM, 3.0–305.0 μM, and 2.5–617.0 μM, respectively. The detection limits (LOD) for DA, UA, and APAP were 0.009 μM, 0.016 μM, and 0.014 μM, respectively. Furthermore, the constructed electrode can be employed to detect the concentration of DA, UA, and APAP in real-samples. This work provides a method for manufacturing highly efficient CePO4 based materials for electrochemical sensing.

Electrochemical sensor based on nickel selenide/hydroxylated multiwalled carbon nanotubes nanocomposites for sensitive detection of maltol

An effective electrochemical sensor based on electrodeposition of nickel selenide nanoparticles (Ni3Se4) on the surface of a glass carbon electrode (GCE) modified with hydroxylated multiwalled carbon nanotubes (MWCNTs-OH) has been successfully developed for determination of maltol. The chemical composition and morphology of Ni3Se4/MWCNTs-OH composites are characterized by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and scanning electron microscopy (SEM). Cyclic voltammetry (CV) and differential pulse voltammetry (DPV) are employed to investigate the electrochemical behavior of maltol at Ni3Se4/MWCNTs-OH/GCE. Consequently, electrochemical sensor based on Ni3Se4/MWCNTs-OH/GCE for detection of maltol displays good electrocatalyst performance. The obtained oxidation peak current of maltol at Ni3Se4/MWCNTs-OH/GCE increases linearly with the increase in concentration of maltol in the range of 0.1 μM–2000 μM, and the calculated detection limit (LOD) is 17.5 nM (S/N = 3). In addition, the fabricated electrochemical sensor shows satisfactory stability, reliable reproducibility and excellent selectivity, and is successfully used to detect maltol in real samples with acceptable accuracy.

Synthesis and Characterization of Palladium/Silver Modified Reduced Graphene Oxide–Nanocomposite Platform for Electrochemical Sensors

AbstractMetal nanoparticles incorporated into carbon nanostructures have tremendous applications in the field of nanosensors and other technologies. Herein, a nanohybrid of reduced graphene oxide modified with silver and/or palladium nanoparticles (Ag/Pd/rGO) was prepared by impregnation of Pd and Ag into the rGO platform and deposited on a glass carbon electrode. Palladium and silver nanoparticles improve the stability and durability of the sensor platform by preventing the agglomeration of graphene oxide sheets and providing chemical stability against environmental factors. This ensures long‐term reliability and repeatability of the sensor performance. The morphologies and microstructures of the as‐prepared nanohybrid were characterized by X‐ray photoelectron spectroscopy, scanning electron microscopy, transmission electron microscopy, X‐ray diffraction, UV–visible and infrared spectroscopy. The average crystallite size of PdAgNPs was found to be between 12 and 15 nm and demonstrated good dispersion across reduced graphene oxide sheets with high‐loading capacities. Thorough investigation of the electrochemical properties of the nanomaterial surfaces through cyclic voltammetry (CV) experiments, revealed distinct redox peaks for Ag+/Ag0 and Pd2+/Pd0 processes and demonstrated the excellent electrochemical properties of the prepared nanocomposites. The rGO‐PdAgNPs‐GCE had a diffusion coefficient value of 1.14×10−14 cm2 s−1 which is acceptable for electrochemical sensors as it is indicative of a fast response time and enhanced sensitivity to changes in gas concentration. The results obtained through thorough characterizations contributes to the novelty of the research by offering a deeper understanding of the material properties and the potential of the nanohybrid material for a broad application scope.

Etching of Ag nanoparticles triggered bidirectional regulation for electrochemiluminescence ratiometric immunoassay.

A highly efficient ratiometric electrochemiluminescence (ECL) immunoassay was explored by bidirectionally regulating the ECL intensity of two luminophors. The immunoassay was conducted in a split-type mode consisting of an ECL detection procedure and a sandwich immunoreaction. The ECL detection was executed using a dual-disk glassy carbon electrode modified with two potential-resolved luminophors (g-C3N4-Ag and Ru-MOF-Ag nanocomposites), and the sandwich immunoreaction using glucose oxidase (GOx)-modified SiO2 nanospheres as labels was carried out in a 96-well plate. The Ag nanoparticles (NPs) acted as bifunctional units both for triggering the resonance energy transfer (RET) with g-C3N4 and for accelerating the electron transfer rate of the Ru-MOF-Ag ECL reaction. When the H2O2 catalyzed by GOx in the 96-well plate was transferred to the dual-disk glass carbon electrode, the doped Ag NPs in the two luminophors could be etched, thus destroying the RET between C3N4 and the accelerated reaction to Ru-MOF, resulting in an opposite trend in the ECL signal outputted from the dual disks. Using the ratio of the two signals for quantification, the constructed immunosensor for a model target, i.e. myoglobin, exhibited a low detection limit of 4.7 × 10-14g/mL. The ingenious combination of ECL ratiometry, bifunctional Ag NPs, and a split-type strategy effectively reduces environmental and human errors, offering a more precise and sensitive analysis for complex samples.

Thioketal-Based Electrochemical Sensor Reveals Biphasic Effects of l-DOPA on Neuroinflammation.

Neuroinflammation is linked closely to neurodegenerative diseases, with reactive oxygen species (ROS) exacerbating neuronal damage. Traditional electrochemical sensors show promise in targeting cellular ROS to understand their role in neuropathogenesis and assess therapies. Nevertheless, these sensors face challenges in mitigating the ROS oxidation overpotential. We herein introduce an ROS oxidation-independent nucleic acid sensor for in situ ROS analysis and therapeutic assessment. The sensor comprises ionizable and thioketal (TK)-based lipids with methylene blue-tagged nucleic acids on a glass carbon electrode. ROS exposure triggers cleavage within the sensor's thioketal moiety, detaching the nucleic acid from the electrode and yielding quantifiable results via square-wave voltammetry. Importantly, the sensor's low potential window minimizes interference, ensuring precise ROS measurements with high selectivity. Using this sensor, we unveil levodopa's dose-dependent biphasic effect on neuroinflammation: low doses alleviate oxidative stress, while high doses exacerbate it. The TK-based sensor offers a promising methodology for investigating neuroinflammation's pathogenesis and screening potential treatments, advancing neurodegenerative disease research.

Ultrasound assisted synthesis of CoFe-LDH for the simultaneous electrochemical detection of dopamine and acetaminophen

Herein, CoFe layered double hydroxide composites (CoFe-LDH) were synthesised by a simple ultrasound assisted synthesis method. It has been characterized by scanning electron microscopy (SEM), X-ray diffraction and X-ray photoelectron spectroscopy. CoFe-LDH modified glass carbon electrode was used as dual-function sensors for DA and AP detection. The sensor exhibits a wide detection linear range for DA and AP (2 μM-900 μM), low detection limits (DA: 0.08 μM; AP: 0.37 μM) (S/N = 3). The sensitivity of CoFe-LDH/GCE for DA and AP were 0.54 μA μM−1 cm−2 and 0.55 μA μM−1 cm−2. And it shows good reproducibility, selectivity, and stability. In addition, the sensor demonstrated good recovery rates for the detection of DA and AP in human serum samples.

Electrochemical aptasensor with signal amplification strategy of covalent organic framework-derived carbon material for ultrasensitive determination of carbendazim

The inadequate conductivity inherent in some covalent organic frameworks (COFs) presents a challenge for their practical use in electrochemical sensors. To enhance the electrical conductivity of COFs, a high-temperature carbonization process can be employed to carbonize COFs in an inert atmosphere, resulting in the production of COF-derived porous carbon materials. In this study, a highly conductive COF-derived carbon material (COF-T800) was obtained through the calcination of a COF known as TPB-DMTP-COF. Cyclic voltammetry (CV) current responses of the TPB-DMTP-COF electrode, when exposed to [Fe(CN)6]3−/4−, were found to be lower compared to those of a bare glassy carbon electrode (GCE). However, after the carbonization of TPB-DMTP-COF, the COF-T800 electrode exhibited significantly higher current responses than bare GCE. The oxidation current response of COF-T800/GCE in [Fe(CN)6]3−/4− was 3.3 times higher than that of TPB-DMTP-COF, demonstrating superior conductivity for this carbonized material. Subsequently, COF-T800 was employed as an electrochemical aptasensor substrate for signal amplification. This aptasensor had ultrasensitive determination of carbendazim (CBZ) with a linear response from 1.0 × 10−12 to 1.0 × 10−7 M. The detection limit of CBZ was 4.0 × 10−13 M. This aptasensor demonstrated high selectivity and applicability for CBZ. The COF-T800-based electrochemical aptasensor was utilized for detecting CBZ in actual samples with success.