Construction Of Electrochemical Biosensors Research Articles

Conductive polymer nanocomposites: recent advances in the construction of electrochemical biosensors

This review focuses on the design, preparation and application of nanostructured CPNs in the construction of advanced electrochemical biosensors in medical diagnostics.

Utilizing Electrochemical Biosensors as an Innovative Platform for the Rapid and On-Site Detection of Animal Viruses.

Animal viruses are a significant threat to animal health and are easily spread across the globe with the rise of globalization. The limitations in diagnosing and treating animal virus infections have made the transmission of diseases and animal deaths unpredictable. Therefore, early diagnosis of animal virus infections is crucial to prevent the spread of diseases and reduce economic losses. To address the need for rapid diagnosis, electrochemical sensors have emerged as promising tools. Electrochemical methods present numerous benefits, including heightened sensitivity and selectivity, affordability, ease of use, portability, and rapid analysis, making them suitable for real-time virus detection. This paper focuses on the construction of electrochemical biosensors, as well as promising biosensor models, and expounds its advantages in virus detection, which is a promising research direction.

Dense Conductive Metal-Organic Frameworks as Robust Electrocatalysts for Biosensing.

Due to the fascinating properties such as high porosity, large surface areas, and tunable chemical components, metal-organic frameworks (MOFs) have emerged in many fields including catalysis, energy storage, and gas separation. However, the intrinsic electrical insulation of MOFs severely restricts their application in electrochemistry. Here, we synthesize a series of 2D conductive MOFs (cMOFs) through tuning the structure with atomic precision using simple hydrothermal methods. Various electroactive probes are used to reveal the structure-property relationships in 2D cMOFs. Then, we demonstrate the first exploration and implementation of 2D cMOFs toward the construction of electrochemical biosensors. In particular, the biosensor based on Cu3(tetrahydroxy-1,4-quinone)2 [Cu3(THQ)2] displays a remarkably improved electrocatalytic performance at a much lower potential. The mechanism study reveals the essential role of charge-transfer interactions between the dense catalytic sites of Cu3(THQ)2 and analytes. Furthermore, the Cu3(THQ)2-based biosensor demonstrates robust anti-interference capability, good stability, fast response speed, and an ultralow detection limit for paraoxon. These promising results indicate the great potential of cMOFs in biomedical, food safety, and environmental sensing applications.

An electrochemical biosensor for exosome detection based on covalent organic frameworks conjugated with DNA and horseradish peroxidase

Quantification of trace exosomes in biofluids is helpful for the early diagnosis of cancers. Electrochemical biosensors have attracted special attentions for exosome detection, while the employment of nanoconjugates in the construction of electrochemical biosensors can achieve better performance. So, in this work, we have designed and fabricated HRP-DNA-COF nanoconjugates (HDCs) that involve covalent organic frameworks (COFs) as the scaffold, cholesterol-tagged DNA to recognize exosomes and horseradish peroxidase (HRP) to amplify the signal readout. The successful preparation of HDCs have been verified experimentally, based on which an electrochemical biosensor has been constructed for exosome detection. Attributed to the specific recognition ability and excellent catalytic ability of HDCs, the biosensor achieves good performance to detect exosomes with simplicity and sensitivity in the linear range from 104 to 107 particles/μL. Besides, the strategy proposed in this work to construct COF-based nanoconjugates may promote the wider application of COFs in biomedical research.

Electrochemical Biosensors with Cross-Linked Hydrogels

Leland C. Clark Jr. and Champ Lyons introduced in 1962 the principle of the first electrochemical biosensor with immobilized glucose oxidase (GOx) [1]. This device was specifically designed and used for fast glucose analysis in blood samples from diabetics. Since then, the biosensor field has experienced important growth. In last few decades, this field has been widely explored in many different environments, such as clinical, biotechnological, food and pharmaceutical. This type of device is object of attention because it allows analysis with high specificity, sensitivity, selectivity and low response time.A key parameter for the proper functioning of electrochemical biosensors is the enzyme immobilization onto the electrochemical interface [2]. Immobilization must be performed in a way that the selected enzyme maintains either structure and spatial orientation. In addition, substrate and product have to be able to diffuse to/from the active site, where the biological reaction takes place. One of the simplest and cost effective immobilization method is the polymer entrapment using natural origin polysaccharides. In that frame, chitosan is currently receiving a great deal of interest because of its intrinsic properties: biocompatible, biodegradable, high abundance, low cost of production and it easily forms hydrogels. However, the poor stability of the hydrogel is of major concern [3] when used as an immobilization strategy in the construction of electrochemical biosensors, since it affects the biosensor lifespan.In the present work, amperometric glucose biosensors based on glucose oxidase (GOx) immobilization onto highly ordered titanium dioxide nanotube arrays (TiO2NTAs) was used to determine the long term stability of the constructed probes. TiO2NTAs were grown by electrochemical anodization of a titanium metal disc in ethylene glycol containing ammonium fluoride (0.3%w/w) and water (2%w/w). The electrochemical synthesis was performed at 30 V for 17 hours. This anodization time yields the maximum sensitivity of the sensor. Higher times result in the nanotube walls collapse. Finally, a thermal annealing was performed at 500 ⁰C for 3 h in air to crystallize TiO2 nanotubes from amorphous to anatase phase.In the sensor architecture chitosan was used as a base material for enzyme immobilization in the hydrogel matrix: Ti/TiO2NTAs/GOx–Chitosan. In order to increase the stability of the immobilization matrix, different crosslinking agents were evaluated onto the chitosan matrix: glutaraldehyde, hypochlorous acid and poly(ethylene glycol) diacrylate. Non-modified chitosan provided a biosensor lifespan around 30 days. In contrast, the used of modified chitosan either increases the long-term stability even the sensitivity of the biosensor.

Inhibition of 2,4-Dichlorophenoxyacetic Acid to Catalase Immobilized on Hierarchical Porous Calcium Phosphate: Kinetic Aspect and Electrochemical Biosensor Construction

The inhibition mechanism of 2,4-dichlorophenoxyacetic acid (2,4-D) to catalase was studied by a catalase biosensor in a flow-injection analysis (FIA) system. This system provides an ideal sensing platform to electrochemically evaluate the chemical mechanism of enzyme inhibition. Hierarchical porous calcium phosphate (hp-CaP), as a biocompatible nanomaterial, was used to immobilize catalase for repeat use. 2,4-D together with H2O2 was injected into the bioreactor of the immobilized catalase-FIA system during the experimental procedure. The activity of the immobilized catalase was inhibited, which caused a decrease of the catalase-catalyzed H2O2 reduction current. Lineweaver–Burk, Dixon, and Cornish–Bowden plots confirmed that the inhibition of catalase by 2,4-D followed an competitive mechanism with a inhibition constant of 4.78 × 10–7 M. Based on this inhibition characters, a biosensor for 2,4-D detection was constructed. This biosensor showed a linear range from 0.03 to 3.00 μM with a detection limit of ...

Prussian Blue/Reduced Graphene Oxide Composite for the Amperometric Determination of Dopamine and Hydrogen Peroxide

Prussian blue has significant application for the construction of electrochemical biosensors. In this work, Prussian blue-reduced graphene oxide modified glass carbon electrodes were successfully fabricated using electrochemical deposition. The high surface area of graphene oxide enhanced the deposition of Prussian blue and the resulting electrocatalytic activity. Infrared spectroscopy and scanning electron microscopy showed that the relatively porous Prussian blue was on the surface of reduced graphene oxide. Cyclic voltammetry showed that Prussian blue-coated reduced graphene oxide composite films improved electron transfer compared to Prussian blue films. The Prussian blue-reduced graphene oxide composite film provided higher response for the reduction of hydrogen peroxide and the oxidation of dopamine compared with the Prussian blue film due to synergistic effects between the reduced graphene oxide and Prussian blue particles. The sensitivity of the electrode was 0.1617 µA µM−1 cm−2. The linear dynamic range extended from 0.5 µM to 0.7 mM dopamine with a limit of detection equal to 125 nM. This work provided a versatile strategy for the design and construction of sensitive amperometric sensors with robust electrocatalytic behavior.

Response of gelatin modified electrode towards sensing of different metabolites.

In this study, a very thin film of biocompatible gelatin B (GB) fabricated onto indium tin oxide (ITO)-coated glass substrate for electrochemical catalytic activity towards different metabolites has been investigated. The optical and electrochemical properties of bare GB/ITO electrode and with different metabolites were characterized by scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR) and electrochemical techniques. The optical properties clearly indicate the structural and surface morphological changes on electrode surface. FTIR spectra showed displacement of the IR peaks towards smaller wave numbers, indicating possible existence of hydrogen bonding between the GB and metabolites. The catalytic behaviour of GB/ITO electrode towards ascorbic acid (AA), citric acid (CA), oxalic acid (OA), glucose (Glu), sucrose (Suc), lactose (Lac) and fructose (Fru) has been investigated by cyclic voltammetry (CV). The electrochemical response studies of GB/ITO electrode have been monitored with different metabolites in the range of 10-500mg/dl. The sensitivity of GB/ITO electrode for AA and OA was found as 0.156 and 0.108μA/(mg/dlcm(-2)) respectively. The results indicate that the GB/ITO electrode has higher specificity towards the AA and OA. The attractive properties of GB/ITO electrode provide the potential applications in the simultaneous detection of AA and OA. The excellent electrocatalytic behaviour of GB/ITO electrode may be useful towards the construction of electrochemical biosensors.

GOLD NANOPARTICLES-BASED BIOSENSORS FOR BIOMEDICAL APPLICATION

Gold nanoparticles are the most extensively studied nanomaterials for biomedical application due to their unique properties, such as rapid and simple synthesis, large surface area, strong adsorption ability and facile conjugation to various biomolecules. The remarkable photophysical properties of gold nanoparticles have provided plenty of opportunities for the preparation of gold nanoparticles-based optical biosensors, while the excellent biocompatibility, conductivity, catalytic properties and large surface-to-volume ratio have facilitated the application of gold nanoparticles in the construction of electrochemical biosensors. In this review, we mainly detail the gold nanoparticles-based optical and electrochemical biosensors for biomedical application in the recent two years, which have exhibited greatly enhanced analytical performances in the detection of DNA, proteins and some important small molecules.

Facile synthesis of flower like copper oxide and their application to hydrogen peroxide and nitrite sensing.

BackgroundThe detection of hydrogen peroxide (H2O2) and nitrite ion () is of great important in various fields including clinic, food, pharmaceutical and environmental analyses. Compared with many methods that have been developed for the determination of them, the electrochemical detection method has attracted much attention. In recent years, with the development of nanotechnology, many kinds of micro/nano-scale materials have been used in the construction of electrochemical biosensors because of their unique and particular properties. Among these catalysts, copper oxide (CuO), as a well known p-type semiconductor, has gained increasing attention not only for its unique properties but also for its applications in many fields such as gas sensors, photocatalyst and electrochemistry sensors. Continuing our previous investigations on transition-metal oxide including cuprous oxide and α-Fe2O3 modified electrode, in the present paper we examine the electrochemical and electrocatalytical behavior of flower like copper oxide modified glass carbon electrodes (CuO/GCE).ResultsFlower like copper oxide (CuO) composed of many nanoflake was synthesized by a simple hydrothermal reaction and characterized using field-emission scanning electron microscopy (FE-SEM) and X-ray diffraction (XRD). CuO modified glass carbon electrode (CuO/GCE) was fabricated and characterized electrochemically. A highly sensitive method for the rapid amperometric detection of hydrogen peroxide (H2O2) and nitrite () was reported.ConclusionsDue to the large specific surface area and inner characteristic of the flower like CuO, the resulting electrode show excellent electrocatalytic reduction for H2O2 and oxidation of . Its sensitivity, low detection limit, fast response time and simplicity are satisfactory. Furthermore, this synthetic approach can also be applied for the synthesis of other inorganic oxides with improved performances and they can also be extended to construct other micro/nano-structured functional surfaces.

Acerate ZnO whiskers and sodium alginate films: preparation and application in bioelectrochemistry of hemoglobin

A novel biocompatible acerate ZnO whiskers (AZW) has been prepared. We explored AZW and sodium alginate for the construction of electrochemical biosensors. The composition, morphology, and size were studied by scanning electron microscopy. UV–vis spectra revealed that hemoglobin (Hb) adsorbed in the acerate ZnO whiskers and sodium alginate retained its native structure. The amperometric response was measured as a function of H2O2 concentration at a fixed potential of −0.25 V in phosphate-buffered saline (pH 7.0). The electrochemical parameters of Hb in acerate ZnO whiskers and sodium alginate were calculated with the results of the electron transfer coefficient (α) and the apparent heterogeneous electron transfer rate constant (k s) as 0.5 and 2.5 s−1, respectively, indicating good facilitation of the electron transfer between Hb and the modified electrode, which may result from the unique nanostructures and larger surface area of acerate ZnO whiskers. The hydrogen peroxide biosensor showed a fast response of <5 s of linear range 2.1 μM–4.8 mM, with a detection of 0.7 μM (S/N = 3). The apparent Michaelis–Menten constant $$ K_m^{{app}} $$ is 0.8 mM. The biosensor possesses high sensitivity, good reproducibility, and long-term stability.

Construction of Biosensor Based on Glassy Carbon Electrode Modified by Composite Film of Multi-Walled Carbon Nanotubes and Poly(ethylenimine)

Multi-walled carbon nanotubes (MWCNTs) were dispersed in an aqueous solution containing water-soluble poly(ethylenimine), and used to prepare MWCNTs modified glassy carbon electrode (GC/MWCNTs). A scanning electron microscopy was employed for characterizing the surface morphology of the modified electrode. The electrochemical behaviors of coenzyme (reduced nicotinamide adenine dinucleotide, NADH) on GC/MWCNTs were studied by both cyclic voltammetry and amperometry, and it is found clearly that the high overpotential for the direct oxidation of NADH on bare GC electrode was largely decreased in the presence of MWCNTs. The GC/MWCNTs electrode exhibited excellent properties as a platform for the construction of electrochemical biosensors based on NAD-dependent dehydrogenases, and an alcohol biosensor was successfully developed by immobilizing alcohol dehydrogenase on GC/MWCNTs.

Immobilization and direct electrochemistry of glucose oxidase on a tetragonal pyramid-shaped porous ZnO nanostructure for a glucose biosensor

A tetragonal pyramid-shaped porous ZnO (TPSP-ZnO) nanostructure is used for the immobilization, direct electrochemistry and biosensing of proteins. The prepared ZnO has a large surface area and good biocompatibility. Using glucose oxidase (GOD) as a model, this shaped ZnO is tested for immobilization of proteins and the construction of electrochemical biosensors with good electrochemical performances. The interaction between GOD and TPSP-ZnO is examined by using AFM, N 2 adsorption isotherms and electrochemical methods. The immobilized GOD at a TPSP-ZnO-modified glassy carbon electrode shows a good direct electrochemical behavior, which depends on the properties of the TPSP-ZnO. Based on a decrease of the electrocatalytic response of the reduced form of GOD to dissolved oxygen, the proposed biosensor exhibits a linear response to glucose concentrations ranging from 0.05 to 8.2 mM with a detection limit of 0.01 mM at an applied potential of −0.50 V which has better biosensing properties than those from other morphological ZnO nanoparticles. The biosensor shows good stability, reproducibility, low interferences and can diagnose diabetes very fast and sensitively. Such the TPSP-ZnO nanostructure provides a good matrix for protein immobilization and biosensor preparation.

The Synergistic Effect of Prussian‐Blue‐Grafted Carbon Nanotube/Poly(4‐vinylpyridine) Composites for Amperometric Sensing

AbstractBecause of its high activity and selectivity toward the reduction of hydrogen peroxide and oxygen, Prussian blue (PB) is usually considered as an “artificial enzyme peroxidase” and has been extensively used in the construction of electrochemical biosensors. In this study, we report on the construction of amperometric biosensors via grafting PB nanoparticles on the polymeric matrix of multiwalled carbon nanotubes (MWCNTs) and poly(4‐vinylpyridine) (PVP). The MWCNT/PVP/PB composite films were synthesized by casting films of MWCNTs wrapped with PVP on gold electrodes followed by electrochemical deposition of PB on the MWCNT/PVP matrix. The electrode modified with the MWCNT/PVP/PB composite film shows prominent electrocatalytic activity toward the reduction of hydrogen peroxide, which can be explained by the remarkable synergistic effect of the MWCNTs and PB. Therefore, fast amperometric response of this sensor to hydrogen peroxide was observed with a detection sensitivity of 1.3 μA μM–1 of H2O2 per square centimeter area and a detection limit of 25 nM. These results are much better than those reported for PB‐based amperometric sensors. In addition, a glucose biosensor fabricated by casting an additional glucose oxidase (GOD) containing Nafion film above the MWCNT/PVP/PB composite film shows promise for the sensitive and fast detection of glucose. The observed high stability, high sensitivity, and high reproducibility of the MWCNT/PVP/PB composite films make them promising for the reliable and durable detection of hydrogen peroxide and glucose.

Electrochemical Biosensors Based on Layer‐by‐Layer Assemblies

AbstractLayer‐by‐layer (LBL) assemblies, which have undergone great progress in the past decades, have been used widely in the construction of electrochemical biosensors. The LBL assemblies provide a strategy to rationally design the properties of immobilized films and enhance the performance of biosensors. The following review focuses on the application of LBL assembly technique on electrochemical enzyme biosensors, immunosensors and DNA sensors.

Studies on Glucose Biosensors Based on Nonmediated and Mediated Electrochemical Oxidation of Reduced Glucose Oxidase Encapsulated Within Organically Modified Sol-Gel Glasses

A new, organically modified sol-gel glass electrode is reported using 3-aminopropyltriethoxy silane and 2-(3,4-epoxycyclohexyl)-ethyltrimethoxy silane as sol-gel precursors for the construction of electrochemical biosensors. Four different systems of new sol-gel glass modified glucose electrodes are made in acidic medium having common sol-gel precursors and: 1) glucose oxidase, 2) glucose oxidase along with polyethylene glycol, 3) glucose oxidase and graphite powder, and 4) glucose oxidase along with polyethylene glycol and graphite powder. Both nonmediated and mediated electrochemical regeneration of immobilized glucose oxidase within sol-gel glasses are studied in these four systems. The nonmediated regeneration is achieved in the presence of oxygen as electron donor whereas mediated regeneration involves soluble ferrocene monocarboxylic acid as electron donor in each system. The electrochemical performance of sol-gel glass based biosensors is compared on the basis of cyclic voltammetry and amperometry. This leads to the observations: i) all four systems reach a diffusion limited condition associated with the transport of soluble ferrocene monocarboxylic acid as well as for dissolved oxygen within the sol-gel matrix, ii) the relative rate of diffusion of these analytes increases from system 1 to system 4, iii) both nonmediated and mediated amperometric responses at suitable potentials are based on the oxidation of H2O2 and enzymatically reduced soluble ferrocene with relatively amplified electrochemical signal of system 4. Data on the reduction of oxygen at conventional graphite disk electrode and at typical sol-gel glass modified electrode are reported.