Electrocatalysis Of Horseradish Peroxidase Research Articles

Simple and sensitive nitric oxide biosensor based on the electrocatalysis of horseradish peroxidase on AuNPs@metal-organic framework composite-modified electrode.

Fe-based metal–organic framework (MIL-101(Fe)) was synthesized through a simple solvothermal synthesis and then used to prepare the AuNPs-decorated MIL-101(Fe) nanocomposite (APPPM(Fe)) by a multi-step layer-by-layer assembly process. Benefited from the porous structure of MIL-101(Fe) and the multilayer assemble process, the loading amount of AuNPs on APPPM(Fe) was enhanced and exhibited a fine biocompatible interface and high conductivity. Through the intense Au–S bond, high loading amount of horseradish peroxidase was immobilized on APPPM(Fe) and the native bioactivity of HRP was kept to realize its direct electrochemistry. From the electrochemical kinetics, the constructed biosensor displayed fast electron transfer and good electrocatalysis activity for the detection of nitric oxide (NO) with wide linear range from 0.033 to 5370 μM and a low detection limit of 0.01 μM (3 σ) as well as fine stability, reproducibility and specificity. According to results of real sample analysis, the proposed electrochemical biosensor offers fast and simple detection of NO in real serum. Therefore, the present strategy definitely provided a potential application prospect in NO clinic detection and disease therapy.Graphical abstract Supplementary InformationThe online version contains supplementary material available at 10.1007/s00604-022-05268-8.

Platinum-3D Graphene Oxide Areogel Nanocomposite for Direct Electrochemistry and Electrocatalysis of Horseradish Peroxidase

Aiming to improve the electron transfer efficiency between redox protein/enzyme and electrode, Pt-3D graphene oxide aerogel (3DGA) nanocomposite was synthesized via a facile one-step hydrothermal method and used as a new biocompatible carrier for protein/enzyme. The morphology and structure of Pt-3DGA nanocomposite were characterized by SEM, TEM, XPS, XRD, Raman and BET. Then a new modified electrode was fabricated with Pt-3DGA-horseradish peroxidase (HRP) biocomposite suspension and Nafion solution coated on carbon ionic liquid electrode (CILE). The performances of Nafion/Pt-3DGA-HRP/CILE were further checked by various methods with the well-maintained 3D structure, good retention of bioactivity of HRP and the enhanced electrochemical ability. Direct electrochemistry of HRP was investigated with a pair of well-shaped redox peaks appeared with the peak-to-peak separation as 78 mV. Electrochemical parameters including electron transfer coefficient (α) and heterogeneous electrode reaction rate constant (ks) are calculated to be 0.52 and 3.35 s−1, respectively. Nafion/Pt-3DGA-HRP/CILE shows outstanding electrocatalytic activity towards trichloroacetic acid (TCA) reduction with a wide detection range of 0.5 ∼ 42.0 mmol/L. Nafion/Pt-3DGA-HRP/CILE can be successfully utilized for the analysis of TCA contents in real samples with good recovery.

A direct electron transfer biosensor based on a horseradish peroxidase and gold nanotriangle modified electrode and electrocatalysis

Gold nanotriangles (AuNTs) were used as a modifier on the surface of a carbon ionic liquid electrode (CILE), which was applied to realize direct electrochemistry and electrocatalysis of horseradish peroxidase (HRP).

Ultrasensitive electrochemical detection for thrombin using hybridization chain reaction with enzyme-amplification

In this work, a new electrochemical aptasensor using hybridization chain reaction (HCR) for signal amplification was developed for highly sensitive detection of thrombin. The sandwich system of aptamer/thrombin/aptamer–primer complex was fabricated as the sensing platform. As the initiator strands, aptamer–primer complex could propagate a chain reaction of hybridization events between the two hairpin probes, and whether long nicked DNA polymers could be formed on the modified electrode. Then the biotin-labeled dsDNA polymers could introduce numerous avidin-labeled horseradish peroxidase (HRP), resulting in significantly amplified electrochemical signal through the electrocatalysis of HRP. On the basis of the enzymatic oxidization of Fe2+ by H2O2 to yield Fe3+, the imaging of thrombin was detected by the reduction current of Fe3+ with the scanning electrochemical microscopic tip. The electrochemical signals had a good linear with logarithm of thrombin concentration in the range from 1.0fM to 100fM, reaching a detection limit of thrombin as low as 0.04fM. In addition, the proposed strategy exhibited excellent specificity and was successfully applied in real sample assay which demonstrated the potential application in clinical diagnostics.

Amperometric aptasensor for thrombin detection using enzyme-mediated direct electrochemistry and DNA-based signal amplification strategy

In this work, a new electrochemical aptasensor based on direct electron transfer and electrocatalysis of horseradish peroxidase (HRP) using exonuclease-catalyzed target recycling and hybridization chain reaction (HCR) for signal amplification was developed for highly sensitive detection of thrombin. The electrochemical signal was originated from HRP without the addition or labeling of redox probes. To construct the aptasensor, the capture probe was immobilized on gold nanoparticles (AuNPs) modified electrode for the following hybridization with the complementary thrombin binding aptamer. In the presence of thrombin, the formation of aptamer–thrombin complex would result in the dissociation of aptamer from the double-strand DNA (dsDNA). Subsequently, with the employment of exonuclease, aptamer was selectively digested and thrombin could be released for analyte recycling. The capture probe and two hairpin helper DNAs lead to the formation of extended dsDNA polymers through HCR on the electrode surface. Then the biotin-labeled dsDNA polymers could introduce numerous avidin-labeled HRP, resulting in significantly amplified electrochemical signal through the direct electrochemistry and electrocatalysis of HRP. The proposed strategy combined the amplification of analyte recycling and HCR, as well as the inherent electroactivity and catalytic activity of HRP, which exhibited high sensitivity for thrombin determination with an ultra-low detection limit of 1.2×10–13 M. Moreover, the detection scheme could be easily extended to the detection of other biomolecules.

Effect of the structure of imidazolium cations in [BF4]−-type ionic liquids on direct electrochemistry and electrocatalysis of horseradish peroxidase in Nafion films

The direct electrochemistry and bioelectrocatalysis of horseradish peroxidase (HRP) in Nafion films at glassy carbon electrode (GCE) was investigated in three [BF(4)](-)-type room-temperature ionic liquids (ILs) to understand the structural effect of imidazolium cations. The three ILs are 1-ethyl-3-methylimidazolium tetrafluoroborate ([Emim][BF(4)]), 1-butyl-3-methylimidazolium tetrafluoroborate ([Bmim][BF(4)]) and 1-hexyl-3-methylimidazolium tetrafluoroborate ([Hmim][BF(4)]). A small amount of water in the three ILs is indispensable for maintaining the electrochemical activity of HRP in Nafion films, and the optimum water contents decrease with the increase of alkyl chain length on imidazole ring. Analysis shows that the optimum water contents are primarily determined by the hydrophilicity of ILs used. In contrast to aqueous medium, ILs media facilitate the direct electron transfer of HRP, and the electrochemical parameters obtained in different ILs are obviously related to the nature of ILs. The direct electron transfer between HRP and GCE is a surface-confined quasi-reversible single electron transfer process. The apparent heterogeneous electron transfer rate constant decreases gradually with the increase of alkyl chain length on imidazole ring, but the changing extent is relatively small. The electrocatalytic reduction current of H(2)O(2) at the present electrode decreases obviously with the increase of alkyl chain length, and the mass transfer of H(2)O(2) via diffusion in ILs should be responsible for the change. In addition, the modified electrode has good stability and reproducibility; the ability to tolerate high levels of F(-) has been greatly enhanced due to the use of Nafion film. When an appropriate mediator is included in the sensing layer, a sensitive nonaqueous biosensor could be fabricated.

Direct electrochemistry and electrocatalysis of horseradish peroxidase with hyaluronic acid–ionic liquid–cadmium sulfide nanorod composite material

A new composite material consisted of hyaluronic acid (HA), ionic liquid 1-butyl-3-methylimidazolium tetrafluoroborate ([BMIM]BF 4) and cadmium sulfide (CdS) nanorod was fabricated and used for the immobilization of horseradish peroxidase (HRP) on the surface of a carbon ionic liquid electrode (CILE), which was prepared with 1-ethyl-3-methyl-imidazolium ethylsulphate ([EMIM]EtOSO 3) as modifier. Spectroscopic results indicated that HRP remained its native structure in the composite film. Based on the synergistic effect of the materials used, an obvious promotion to the direct electron transfer efficient between HRP and CILE was achieved with a pair of well-defined redox peaks appeared in 0.1 mol L −1 phosphate buffer solution, indicating the realization of the direct electrochemistry of HRP. The immobilized HRP showed good electrocatalytic activity towards the reduction of trichloroacetic acid and H 2O 2 with the electrochemical parameters calculated. Based on the fabricated electrode, a new third-generation electrochemical biosensor was constructed with good stability and reproducibility.

Three-dimensionally ordered macroporous (3DOM) gold-nanoparticle-doped titanium dioxide (GTD) photonic crystals modified electrodes for hydrogen peroxide biosensor

Gold nanoparticles have been introduced into the wall framework of titanium dioxide photonic crystals by the colloidal crystal template technique. The three-dimensionally ordered macroporous gold-nanoparticle-doped titanium dioxide (3DOM GTD) film was modified on the indium-tin oxide (ITO) electrode surface and used for the hydrogen peroxide biosensor. The direct electron transfer and electrocatalysis of horseradish peroxidase (HRP) immobilized on this film have been investigated. The 3DOM GTD film could provide a good microenvironment for retaining the biological bioactivity, large internal area, and superior conductivity. The HRP/3DOM GTD/ITO electrode exhibited two couples of redox peaks corresponding to the HRP intercalated in the mesopores and adsorbed on the external surface of the film with the formal potential of −0.19 and −0.52V in 0.1M PBS (pH 7.4), respectively. The HRP intercalated in the mesopores showed a surface-controlled process with a single proton transfer. The direct electron transfer between the adsorbed HRP and the electrode is achieved without the aid of an electron mediator. The H2O2 biosensor displayed a rapid eletrocatalytic response (less than 3s), a wide linear range from 0.5μM to 1.4mM with a detection limit of 0.2μM, high sensitivity (179.9μAmM−1), good stability and reproducibility. Compared with the free-Au doped titanium dioxide photonic crystals modified electrode, the GTD modified electrode could greatly enhance the response current signal, linear detection range and higher sensitivity. The 3DOM GTD provided a new matrix for protein immobilization and direct transfer study and opened a way for low conductivity electrode biosensor.

Direct Electron Transfer of Horseradish Peroxidase and Its Biosensor Based on Gold Nanoparticles/Chitosan/ITO Modified Electrode

Gold nanoparticles/chitosan modified indium tin oxide (ITO) coated glass electrode was prepared by a simple layer-by-layer self-assembly technique. Horseradish peroxidase (HRP) was successfully immobilized on the modified electrode by electrostatic adsorption. Direct electrochemistry and electrocatalysis of HRP were investigated. The composite film showed an obvious promotion for the direct electron transfer between HRP and the underlying electrode. The immobilized HRP exhibited an excellent electrocatalytic activity toward the reduction of H2O2. The catalysis currents increased linearly to the H2O2 concentration in a wide range of 2.0 × 10−5 to 6.5 × 10−3 M with a low detection limit of 3.5 × 10−6 M. The calculated apparent Michaelis-Menten constant (K ) was 4.43 mM.

Direct electrochemistry and electrocatalysis of horseradish peroxidase in α-zirconium phosphate nanosheet film

α-zirconium phosphate nanosheets (ZrPNS) derived via the delamination of layered α-zirconium phosphate (α-ZrP) have been proven to be efficient support matrixes for the immobilization of horseradish peroxidase (HRP). X-ray powder diffraction (XRD) results revealed that ZrPNS in HRP–ZrPNS film remained unorderly structured for the effect of HRP. Fourier transform infrared (FTIR) spectra results revealed that HRP remained the secondary structure in HRP–ZrPNS film. The direct electrochemistry of HRP was realized in HRP–ZrPNS film on a glassy carbon electrode (GCE), showing a pair of well-defined, nearly reversible cyclic voltammetry (CV) peaks for the HRP heme FeIII/FeII redox couple. The average surface concentration (Γ⁎) of electroactive HRP in HRP–ZrPNS film was estimated to be 1.35×10−10 mol cm−2, which indicated a high loading of enzyme molecules in HRP–ZrPNS film. Based on these, a third generation reagentless biosensor was constructed for the determination of hydrogen peroxide (H2O2). The response time of the biosensor was less than 3 s, and the linear response range of the biosensor for H2O2 was from 1.3×10−6 to 1.6×10−2 M with a correlation coefficient of 0.9997.

Direct electrochemistry and electrocatalysis of horseradish peroxidase in MnO2 nanosheet film

A novel material MnO2 nanosheet has been used as the support matrix for the immobilization of horseradish peroxidase (HRP). HRP entrapped in MnO2 nanosheet film exhibits facile direct electron transfer with the electron transfer rate constant of 6.86 s−1. The HRP/MnO2 nanosheet film gives a reversible redox couple with the apparent formal peak potential (E 0) of −0.315 V (vs. Ag/AgCl) in pH 6.5 phosphate buffer solution (PBS). The formal potential E 0 of HRP shifts linearly with pH with a slope of −53.75 mV · pH−1, denoting that an electron transfer accompanies single-proton transportation. The immobilized HRP shows an electrocatalytic activity to the reduction of H2O2. The response time of the biosensor for H2O2 is less than 3 s, and the detection limit is 0.21 μmol · L−1 based on signal/noise = 3.

Electrocatalysis of Horseradish Peroxidase Immobilized on Cobalt Nanoparticles Modified ITO Electrode

It is the first time that Horseradish peroxidase (HRP) was successively immobilized on the magnetic cobalt nanoparticles modified ITO (indium tin oxide) electrode. Morphologies of electrode surface were featured by the field emission‐scanning electron microscope (FSEM). Cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) were used to characterize the modified process of electrode. Direct electrochemistry and electrocatalysis of HRP immobilized on nano‐Co/ITO were investigated. The biosensor exhibited high sensitivity, good stability, and excellent electrocatalytic activity to the reduction of H2O2. Under the optimized experimental conditions, a calibration curve over 2.0×10−9∼2.0×10−8 mol l−1 and 2.0×10−7∼2.0×10−6 mol l−1, with a limit of detection of 1.9×10−9 mol l−1 was obtained. The apparent Michaelis‐Menten constant (K M app ) for HRP/nano‐Co/ITO electrode was calculated to be 0.79 mmol l−1, indicating a higher affinity of HRP attached on the modified electrode.

Direct electrochemistry of horseradish peroxidase in gelatin-hydrophobic ionic liquid gel films

Abstract The direct electrochemistry and electrocatalysis of horseradish peroxidase (HRP) immobilized on a gelatin – N , N -dimethylformamide (DMF) – hydrophobic ionic liquid (i.e. 1-octyl-3-methylimidazolium hexafluorophsohate) gel film coated glassy carbon electrode has been studied for the first time. The immobilized HRP exhibits a pair of well-defined quasi-reversible peaks in pH 7.0 phosphate buffer solutions, which results from the direct electron transfer between the enzyme and the underlying electrode. In this case there is about 2.7% of the immobilized HRP undergoing the electrochemical reaction, which corresponds to multi-layer of HRP on the electrode surface. The HRP immobilized has higher thermal stability than in gelatin hydrogel. Experiment results also show that the voltammetric behavior of the enzyme electrode depends on the type of room temperature ionic liquid (RTIL) used. When a more hydrophobic RTIL is adopted, the resulting enzyme electrode gives better performance. In the presence of hydrogen peroxide, the enzyme electrode shows sensitive response. The sensitivity of the catalytic peak is up to 1.38 A cm −2 M −1 and the Michaelis constant is down to 6.84 × 10 −5 M, which are superior to that reported elsewhere. In addition, the UV–visible spectra of HRP entrapped in different films and the mass transfer of hydrogen peroxide are discussed as well.

Direct electron transfer of horseradish peroxidase and its biosensor based on chitosan and room temperature ionic liquid

A reagentless horseradish peroxidase (HRP) biosensor, which is based on the direct electron transfer between the enzyme and the electrode, has been shown by direct electrochemistry of HRP and direct bioelectrocatalysis towards H 2O 2. Composite material based on biocompatible chitosan (Chi) and room temperature ionic liquid 1-butyl-3-methyl-imidazolium tetrafluoroborate (BMIM · BF 4) was used to construct the HRP biosensor. A pair of stable and well-defined quasi-reversible redox peaks of HRP for the HRP(Fe(III))/HRP(Fe(II)) redox couple with a formal potential of about −0.34 V (vs. Ag/AgCl) in a pH 7.0 phosphate buffer solution (PBS) were observed at the Chi-BMIM · BF 4-HRP composite film modified glassy carbon (GC) electrode. The biosensor exhibited good sensitivity and reproducibility, wide linear range, low detection limit and excellent long-term stability. The Chi-BMIM · BF 4-HRP film was also characterized by UV–visible spectroscopy, indicating that HRP in the composite film could retain its native structure. Both biocompatibility of chitosan and inherent conductivity of BMIM · BF 4 enable the composite material to become an excellent biosensing platform for realizing direct electrochemistry and electrocatalysis of HRP along with good stability.

Mesoporous Materials Promoting Direct Electrochemistry and Electrocatalysis of Horseradish Peroxidase

AbstractThe direct electron transfer and electrocatalysis of horseradish peroxidase (HRP) immobilized on hexagonal mesoporous silicas (HMS) matrix was studied. The interaction between HRP and HMS was examined by using Fourier transform infrared spectroscopy, nitrogen adsorption isotherms and electrochemical methods. The immobilized HRP at a modified glassy carbon electrode showed a good direct electrochemical behavior, which depended on the specific properties of the HMS. Two couples of redox peaks corresponding to Fe(III) to Fe(II) conversion of the HRP intercalated in the mesopores and adsorbed on the external surface of the HMS were observed with the formal potentials of −0.315 and −0.161 V in 0.1 M pH 7.0 PBS, respectively. The amount of HRP intercalated in the mesopores of HMS proved to be related to the pore size. The HRP intercalated in the mesopores showed a surface controlled electrode process with a single proton transfer. The immobilized HRP displayed an excellent electrocatalytic response to the reduction of hydrogen peroxide (H2O2) without the aid of an electron mediator. The HMS provided a novel matrix for protein immobilization and direct electron transfer study of the immobilized protein.