Electrochemical Detection Research Articles

Internal-driven DNA nanowindmill: Multi-fulcrum mediated amplified rolling nanomachine for fast and ultrasensitive electrochemical detection of tau

Inspired by the wind driving windmill rolling to generate electrical energy, we have fabricated a multi-fulcrum mediated amplified rolling nanomachine (MFN) for Tau detection with the internal drive. The MFN backbone is DNA nanowindmill (DM) self-assembled from DNA, which is initially ineffective and finally activated into an effective DM through interaction with Tau followed by the magnetic separation. The DM is introduced to the electrode interface where it continues rolling under the drive of the multi-fulcrum and signal probe to achieve signal amplification. On one hand, the modular design and DM rolling feeds the impediment of signal transduction and amplification due to spatial hindrance during protein detection. On the other hand, it endows fast response and high sensitivity. The proposed MFN electrochemical biosensor is successfully applied to detect Tau ranging from 10 pg/mL to 2 μg/mL with low detection limit of 127 fg/mL, which is much lower than the pathological state concentration of Tau ∼400 pg/mL. Furthermore, our findings proves that MFN can successfully differentiate normal individuals from Alzheimer’s disease (AD) patients based on clinical samples analysis.

Carbon Nanotubes and Their Composites for Flexible Electrochemical Biosensors

AbstractFlexible biosensors play a crucial role for healthcare management and disease diagnosis. Electrochemical biosensors have attracted significant attention for wearable sensing applications owing to their numerous advantages, including high sensitivity and selectivity, inherent miniaturization and rapid response times. Challenges lie in the development of highly conductive and flexible electrodes that can be integrated with biorecognition components to engineer selective biosensor interfaces. Carbon nanotubes (CNTs) hold significant promise as materials for wearable flexible sensor fabrication. This review highlights recent strategies for fabricating conductive and flexible electrodes, whether in the form of films or fibers, based on CNTs and their composites. Additionally, the review explores emerging biosensing applications, including flexible sensors for the direct electrochemical detection of biomarkers, sensors functionalized with enzymes, antibodies, or DNA, and sensors interfaced with cells to monitor transient biochemical signals.

A nickel porphyrin-based covalent organic framework modified electrode for the electrochemical detection of acetaminophen.

Covalent organic frameworks (COFs) can be rationally designed with functional organic ligands to improve the electrochemical responsiveness of the electrode toward certain medicinal compounds. In this study, we synthesized a COF-Ni electrocatalyst material, which is formed by covalent coupling of electron-rich 2,3,6,7-tetrakis (4-formylphenyl) tetrakis (4-imidazolyl) (TTF-4CHO) and hole-rich 5,10,15,20-tetrakis (4-aminophenyl) porphyrin nickel(II) (TAPP-Ni). The reasonable electron transfer path design, the large specific surface area of the COF and the physical properties of ordered nanopores, as well as the Ni-N4 bond as a highly active catalytic center, allow the COF-Ni material modified electrode to exhibit excellent sensing performance for acetaminophen (ACOP). The detection limit for ACOP is as low as 47.6 nM, with a linear range of 1-1500 μM, which is better than for most of the reported sensors. With superior interference resistance and good stability performance, COF-Ni is a highly suited electrode modification material for real-world sample detection, which provided a new perspective for application of COF materials in drug analysis.

Progressions in Modified Graphite Electrodes with Green Nanostructured Materials for Low Cost and Sustainable Electrochemical Detection of Environmental Contaminants

Progressions in Modified Graphite Electrodes with Green Nanostructured Materials for Low Cost and Sustainable Electrochemical Detection of Environmental Contaminants

Non-enzymatic electrochemical detection of sarcosine in serum of prostate cancer patients by CoNiWBO/rGO nanocomposite

Selective and sensitive sarcosine detection is crucial due to its recent endorsement as a prostate cancer (PCa) biomarker in clinical diagnosis. The reduced graphene oxide-cobalt nickel tungsten boron oxides (CoNiWBO/rGO) nanocomposite is developed as a non-enzymatic electrochemical sensor for sarcosine detection in PCa patients’ serum. CoNiWBO/rGO is synthesized by the chemical reduction method via a one-pot reduction method followed by calcination at 500 °C under a nitrogen environment for 2 h and characterized by UV-Vis, XRD, TGA, and SEM. CoNiWBO/rGO is then deposited on a glassy carbon electrode, and sarcosine sensing parameters are optimized, including concentration and pH. This non-enzymatic sensor is employed to directly determine sarcosine in serum samples. Differential pulse voltammetry (DPV) and linear sweep voltammetry (LSV) are employed to monitor the electrochemical behavior where sarcosine binding leads to oxidation. Chronoamperometric studies show the stability of the developed sensor. The results demonstrate a wide linear range from 0.1 to 50 µM and low limits of detection, i.e., 0.04 µM and 0.07 µM using DPV and LSV respectivel. Moreover, the calculated recovery of sarcosine in human serum of prostate cancer patients is 78–96%. The developed electrochemical sensor for sarcosine detection can have potential applications in clinical diagnosis.

Vertical Microfluidic Trapping System for Capturing and Simultaneous Electrochemical Detection of Cells.

Electrochemical impedance spectroscopy (EIS) is a non-invasive and label-free method widely used for characterizing cell cultures and monitoring their structure, behavior, proliferation and viability. Microfluidic systems are often used in combination with EIS methods utilizing small dimensions, controllable physicochemical microenvironments and offering rapid real-time measurements. In this work, an electrode array capable of conducting EIS measurements was integrated into a multichannel microfluidic chip which is able to trap individual cells or cell populations in specially designed channels comparable to the size of cells. An application-specific printed circuit board (PCB) was designed for the implementation of the impedance measurement in order to facilitate connection with the device used for taking EIS spectra and for selecting the channels to be measured. The PCB was designed in consideration of the optical screening of trapped cells in parallel with the EIS measurements which allows the comparison of EIS data with optical signals. With continuous EIS measurement, the filling of channels with cell suspension can be followed. Yeast cells were trapped in the microfluidic system and EIS spectra were recorded considering each individual channel, which allows differentiating between the number of trapped cells.

3D printed microfluidic devices with electrodes for electrochemical analysis.

A review with 93 references describing various 3D printing approaches that have been used to create microfluidic devices containing electrodes for electrochemical detection. The use of 3D printing to fabricate microfluidic devices is a rapidly growing area. One significant research area is how to detect analytes in the devices for quantitation purposes. This review article is focused on methods used to integrate electrodes into the devices for electrochemical detection. The review is organized in terms of the methodology for integrating the electrode within the device. This includes (1) external coupling of traditional electrode materials with 3D printed devices; (2) printing conductive electrode materials as part of device printing; and (3) integrating traditional electrodes into the device as part of the print process. Example applications are given and some future directions are also outlined.

Lithium Niobate Perovskite as the Support for Silver Nanoparticles for Non-Enzymatic Electrochemical Detection of Glucose

Lithium niobate perovskite and silver nanoparticle-based nanocomposites (LNB:AgNPs) were explored for developing an electrochemical glucose sensor. The perovskite to silver nanoparticle ratios investigated were 4:1, 1:1, 1:2, 2:1, and 1:4. Among these, the 4:1 ratio, with the lowest silver content, demonstrated the most stable performance during glucose quantification via amperometry. The sensor’s response was evaluated measuring the current at a fixed potential of 0.7 V following the injection of 1 mM glucose with each addition. The calibration curve obtained from the recorded data exhibited a linear response within the 1 to 15 mM glucose concentration range, achieving a sensitivity of 2 μA/mM, a high correlation coefficient (R2 = 0.997), and a limit of detection (LOD) of 0.5 µM. The LNB4:1AgNP composite allowed taking advantage of the unique properties of both components in a balanced manner, maximizing the sensor performance in practical applications.

Fabrication of Co/Zn Doped Manganese Ferrite Magnetic Nanoparticles: Improving Electrochemical Detection of Antibiotic Through Modification of Reduced Graphene Oxide

Fabrication of Co/Zn Doped Manganese Ferrite Magnetic Nanoparticles: Improving Electrochemical Detection of Antibiotic Through Modification of Reduced Graphene Oxide

Efficient Multidriven Strand Displacement Reaction for Biosensing.

A key challenge for achieving high-efficient DNA strand displacement reaction (SDR) with existing technologies is the inferior kinetic performance due to the alternately cumbersome conjunction and dissociation of dsDNA. In this work, a novel multidriven SDR collaborated by toehold initiator, strand towing, and click chemistry is engineered. The invasion strand (O) endows the hybridization with a basal strand (M) in dsDNA for releasing a displacement strand (P), which can be significantly boosted by the towing of a helper strand and impetus from the click reaction. Accordingly, the hybridization rate and dissociation extent of P can be largely improved and showed a desiring displacement rate close to 6-fold compared with the traditional method, providing a newly high-efficient SDR strategy for potential application in biosensing, clinical diagnostics, and DNA nanotechnology. In view of this, a practical biosensing platform by combining the multidriven SDR (MSDR) with waste-free DNA multi-cycle amplification is constructed for the rapid and ultrasensitive electrochemical detection of cancer-related miRNA-21. The substantial output DNA as an invasion strand (O) from target-triggered waste-free DNA multicycle can high-efficiently release a signal probe (Fc)-labeled displacement strand (P) on an electrode by using the proposed MSDR, obtaining a low detection limit below 106.8 aM.

Minimally Invasive Real-Time Monitoring for Rapid and Sensitive Diagnosis of Spinal Cord Injury.

Spinal cord injury (SCI) is a serious neurological injury that is currently extremely difficult to cure clinically. SCI involves numerous pathophysiological processes, and microRNAs (miRNAs) play an important role in these processes. Meanwhile, miRNAs have received a lot of attention for their role in other diseases as well. Therefore, the detection of disease-related miRNAs is important for the study of disease development, treatment, and prognosis. With the rapid development of molecular biology, the traditional detection methods of miRNA can no longer meet the needs of experiments. Electrochemical detection methods are widely used because of their excellent detection performance. Here, we designed an electrochemical sensor prepared using borosilicate glass microneedle electrodes for real-time monitoring of miR-21-5p expression in vivo after SCI. The sensor showed a good linear relationship between the oxidation peak current value and the concentration of miR-21-5p in the concentration range 0-2 fM (Y = 12.025X + 90.396, R2 = 0.98). The limit of detection (LOD) of the sensor was 0.3667 fM. The experimental results showed that the borosilicate glass microneedle electrochemical sensor achieved fast, accurate, highly sensitive, highly specific, highly stable, and reproducible monitoring of miR-21-5p. More importantly, the electrochemical sensor has a better clinical translation prospect, which is important for the research of clinical diseases.

Self‐Calibrating Copper‐Based Metal Organic Frameworks for Ratiometric Electrochemical Sensing of Creatinine

AbstractNanostructures that can undergo redox reactions have significant potential for electrochemical analysis. They can act as signal amplifiers to determine concentrations of targets in biological samples. In this work, a rational combination of electroactive copper‐based metal‐organic frameworks (Cu‐MOFs) and ferrocene carboxylic acid (Fc) was designed for ratiometric electrochemical detection of creatinine. The synthesized Fc@Cu‐MOFs exhibited two redox signals from the Cu2+/Cu+ and Fe3+/Fe2+ systems in the skeleton of Cu‐MOFs and Fc, respectively. In the presence of chloride (Cl−), the oxidation current of Cu+ increased due to formation of solid‐state cuprous chloride (CuCl). Adding strong Cu+ chelators, e. g. creatinine, coordinated with Cu+ and caused the current output of solid‐state CuCl to decrease significantly. The anodic current of Fc did not appreciably change, serving as an internal reference signal. The ratiometric responses (ICu(I)/IFc) changed with increasing concentrations of creatinine from 0.017–130 μM with a detection limit (S/N=3) of 0.005 μM. The main advantages of Fc@Cu‐MOFs are the low LOD, high selectivity, and reliability, making it a suitable platform for determining creatinine in human serum and urine samples. The as‐fabricated sensor is a reliable approach for determining (bio) molecules that can form stable complexes with Cu+ ions.

Nanofloral BiVO4/rGO composites for sensitive electrochemical detection of furazolidone in water

Antibiotics are widely used in agriculture, animal husbandry, and aquaculture, and the development of efficient, sensitive, and convenient antibiotic trace detection techniques is beneficial for tracking their transfer behavior in the environment. Electrochemical sensors have recently shown significant promise in the detection of antibiotics, however, the complex composition of the aqueous environment may interfere with the sensitivity and accuracy of the electrodes during electrochemical detection, and the selection of appropriate nanocomposites for modifying the electrodes has been considered as an effective solution. Nanofloral BiVO4/rGO electrocatalysts were developed for the electrochemical detection of furazolidone (FZD) based on a robust green sonochemical approach. the large specific surface area and excellent electrical conductivity of the BiVO4/rGO composites efficiently catalyzed the electrochemical reaction of FZD, which led to the improvement in the detection sensitivity and stability of the sensors. It exhibits current amplification and electrocatalytic effects in the reduction reaction of furazolidone. The assay exhibited a wide linear range, low detection limit, good reproducibility, stability and anti-interference properties, and a simple and convenient preparation process. The effects of conditions such as scanning rate (v), electrolyte pH, and electrode loading on the detection effect were investigated, developed BiVO4/rGO composites exhibited detection limits of 1.46 and 22.4 nM and sensitivities of 24.4 and 1.94 μA μM−1 cm−2, respectively, for FZD. The objective of the study is to provide a novel, low-cost, convenient and highly sensitive assay for the detection of antibiotics in the aqueous environment. BiVO4/rGO electrocatalysts are ideal candidates for low-cost, convenient and highly sensitive detection of antibiotics in aqueous environments, promoting the technological development and application in this field.

Cobalt‐Based Ferrite Modified Carbon Nanotubes Fibers for Flexible and Disposable Microelectrode Toward Electrochemical Glucose Sensing

ABSTRACTGlucose detection is critical in clinical health and the food industry, particularly in the diagnosis of blood sugar levels. Carbon‐based fiber materials have recently featured prominently as non‐enzymatic electrochemical glucose detectors. Herein, cobalt‐based ferrite (CoFe2O4) in the form of nanoparticles has been successfully fabricated over the carbon nanotubes (CNTs) fiber via a simple hydrothermal process. Fabricated microelectrode (CoFe2O4@CNTs) was investigated as an electrocatalyst toward the non‐enzymatic electrochemical glucose sensors. The structure and morphology of the modified fiber were studied by scanning electron microscopy including energy‐dispersive X‐ray spectroscopy. The electrochemical capability of the microelectrode was analyzed by using different electrochemical techniques including cyclic voltammetry, chronoamperometry, and electrochemical impedance spectroscopy (EIS). The proposed sensors exhibited a superb sensitivity of 0.21 µAcm−2 mM−1, a good linear range from 1 to 9 mM, and a lower detection limit of 1.7 mM. Further investigation via EIS indicated the low charge transfer resistance as compared to the bare CNTs‐based fiber. Outcomes revealed that the material can potentially prove promising for the disposable microelectrode toward electrochemical glucose sensing.

Enzymatic and Enzyme‐Free Electrochemical Lactate Sensors: A Review of the Recent Developments

ABSTRACTLactate is a useful analytical indicator in various fields. The lactate monitoring benefits from evaluating the body's condition, as excessive muscle use or fatigue can result in injury. Further, it is useful for alerting to emergencies like haemorrhage, hypoxia, respiratory distress, and sepsis. Additionally, the determination of the food's lactate level is very important in examining freshness, storage stability, and fermentation degree. Given such benefits, the determination of lactate in various samples has been widely explored, especially using electrochemical sensor technology. Despite enzymatic sensors being the focus of numerous studies, enzyme‐free platforms have gained focus over the last few years to address the matter of enzyme stability. This review article respectfully offers an overview of the concepts, applications, and recent advances of electrochemical lactate detection platforms. A comparison of hot research for enzymatic and enzyme‐free lactate sensors in terms of electrode surface engineering, enzymes and their immobilisation matrices, and several analytical parameters, including linear dynamic range, the limit of detection, sensitivity, and stability, have been discussed. In addition, future perspectives have been highlighted in this review.

Facile green preparation of ZnFe2O4 nanoparticles using papaya leaf extract for electrochemical detection of acetaminophen in Zerodol P and Dolo drops

Facile green preparation of ZnFe2O4 nanoparticles using papaya leaf extract for electrochemical detection of acetaminophen in Zerodol P and Dolo drops

Graphenic materials prepared from magnesium ions doping cellulose and its application in electrochemical detection of adenine and guanine

Graphenic materials of high quality are in high-demand. In this study, a method is proposed for the synthesis of graphenic materials by the pyrolysis of cellulose materials. Cellulose materials were oxidized and doped with magnesium prior to pyrolysis, which improved the graphitization efficiency significantly. The obtained graphenic materials, exhibiting a well-developed porous structure, high specific surface area, were employed for the fabrication of a composite electrode. The composite electrode was employed for the simultaneously detection of adenine (AE) and guanine (GA) with excellent performance in the electrocatalytic oxidation response. Various electrochemical tests were carried out to optimized the detection of AE and GA. Under the optimized conditions, the simultaneous quantification of GA and AE is achieved from 1 – 100 μM with detection limits from 0.4 – 0.6 μM. This study offers a promising alternative for the synthesis of graphenic materials of high quality.

ZnO Nanorods Aligned in a Vertical Configuration for Targeted Electrochemical Detection of Aniline.

This study demonstrates the synthesis of 1D surface vertically aligned nanorods of ZnO on the fluorine-doped tin oxide-coated glass substrate (ZnO-VANRs/FTOs) synthesized via a chemical route for the targeted electrochemical sensing of aniline. The ZnO-VANRs/FTOs were 1.57 ± 0.03 μm in length with excellent crystallinity and high density (1.52 × 1013 rod no./m2). ZnO-VANRs formation increased surface roughness by 2.4- and 4.7-fold compared to the bare FTOs and seeded FTOs (ZnO-seed/FTOs), respectively. The ZnO-VANRs/FTOs electrodes could increase the effective surface area from 0.154 to 0.384 cm2 with about 86.85% reduction in charge transfer resistance compared to the bare FTOs. The peak current response (at 0.281 V vs Ag/AgCl) of aniline deposition was boosted by 81.52% with the rise in temperature from 15 to 45 °C. The reduction of aniline at ZnO-VANRs/FTOs involved a reversible two-electron diffusion control process with a heterogeneous reaction rate constant (k0) of 1.82 s-1 and a formal potential (E0) of 0.289 V vs Ag/AgCl. The ZnO-VANRs/FTOs electrode showed limits of detection of 0.193 μM (sensitivity 0.198 μA·μM-1·cm-2) and 0.588 μM (sensitivity of 0.065 μA·μM-1·cm-2) between the working ranges of 0-20 and 20-160 μM, respectively. The fabricated sensor was unprecedently selective toward aniline sensing, and p-nitroaniline, chlorobenzene, chlorpyrifos, Cu2+, Pb2+, Ni2+, Cd2+, albumin bovine, Escherichia coli, and ciprofloxacin could not interfere with aniline sensing and its sensitivity. However, the peak current was marginally decayed by 2.63% up to the 6th cycle. Moreover, ZnO-VANRs/FTOs catalyzed the sensing of aniline spiked in the environmental matrices, conforming well to liquid chromatography.

Zr-MOF Nanospheres on Zn-MOF Nanorods on Ni Foam for the Electrochemical Detection of Ivermectin in Urine Samples

Zr-MOF Nanospheres on Zn-MOF Nanorods on Ni Foam for the Electrochemical Detection of Ivermectin in Urine Samples

Cobalt vanadate intertwined in carboxylated multiple-walled carbon nanotubes for simultaneous electrochemical detection of ascorbic acid, dopamine and uric acid

Low-cost transition metal vanadate-based electrochemical sensors have attracted a lot of attention recently. A cobalt vanadate and carboxylated multi-walled carbon nanotube composite (CoV/MWCNTs-COOH) was prepared by an ultrasonic-assisted assembly method. The uniform and dense MWCNTs-COOH attached to the surface of CoV not only combines the large surface area and superior conductivity of MWCNTs-COOH with the excellent electrochemical activity of CoV, but also enhances the redox reaction between CoV/MWCNTs-COOH composite and the analyte through synergistic effect of hydrogen bonding and electrostatic interaction. The electrochemical behaviors of CoV/MWCNTs-COOH composite modified glassy carbon electrode (CoV/MWCNTs-COOH/GCE) were investigated by cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS) and differential pulse voltammetry (DPV). The simultaneous electrochemical sensing of ascorbic acid (AA), dopamine (DA) and uric acid (UA) on CoV/MWCNTs-COOH/GCE possesses good peak current signals with well-defined peak potentials. The linear ranges of AA, DA, and UA at CoV/MWCNTs-COOH/GCE are 1.0–100.0 μM, and the limits of detection (LODs; S/N = 3) are 0.4 μM, 0.03 μM, and 0.1 μM, respectively. The practicality of the designed sensor was further confirmed by the good recoveries obtained in the simultaneous measurement of actual samples including fetal bovine serum, human serum, urine, and Vitamin C tablets. Overall, the developed electrochemical sensor shows potential therapeutic applications for simultaneous determination of AA, DA and UA in biological fluids.