Direct Electron Transfer Of Mb Research Articles

Myoglobin- and Hydroxyapatite-Doped Carbon Nanofiber-Modified Electrodes for Electrochemistry and Electrocatalysis.

In this paper, a hydroxyapatite (HAp)-doped carbon nanofiber (CNF)-modified carbon ionic liquid electrode (CILE) was prepared and used for the investigation on the direct electrochemistry and electrocatalysis of myoglobin (Mb). HAp nanoparticles were mixed within a polyacrylonitrile (PAN) solution, and a HAp@PAN nanofiber was synthesized by electrospinning process, which was further controlled by carbonization at 800 °C for 2 h in a nitrogen atmosphere to get a HAp@CNF nanocomposite. Various techniques were used to check the physicochemical properties of HAp@CNF. Mb was mixed with a HAp@CNF dispersion solution and casted on the surface of CILE to obtain an electrochemical sensing platform. The direct electrochemistry of Mb on the modified electrode was checked when a pair of enhanced redox waves appeared, indicating the direct electron transfer of Mb. HAp@CNF exhibited high conductivity, good biocompatibility, and large surface area, which was beneficial for Mb immobilization. The modified electrode showed excellent electrocatalytic activity toward the reduction of trichloroacetic acid and sodium nitrite, which was further used to establish a new electroanalytical method. Real samples were analyzed by the proposed method with satisfactory results.

A novel biosensor based on electro-co-deposition of sodium alginate-Fe3O4-graphene composite on the carbon ionic liquid electrode for the direct electrochemistry and electrocatalysis of myoglobin

A novel biosensor based on electro-co-deposition of myoglobin (Mb), sodium alginate (SA), Fe3O4-graphene (Fe3O4-GR) composite on the carbon ionic liquid electrode (CILE) was fabricated using Nafion as the film forming material to improve the stability of protein immobilized on the electrode surface, and the modified electrode was abbreviated as Nafion/Mb-SA-Fe3O4-GR/CILE. FT-IR and UV–vis absorption spectra suggested that Mb could retain its native structure after being immobilized in the SA-Fe3O4-GR composite film. The electrochemical behavior of the modified electrode was studied by cyclic voltammetry, and a pair of symmetric redox peaks appeared in the cyclic voltammograms, indicating that direct electron transfer of Mb was realized on the modified electrode, which was ascribed to the good electrocatalytic capability of Fe3O4-GR composite, the good biocompatibility of SA and the synergistic effects of SA and Fe3O4-GR composite. The electrochemical parameters of the electron transfer number (n), the charge transfer coefficient (α) and the electron transfer rate constant (k s) were calculated as 0.982, 0.357 and 0.234 s−1, respectively. The modified electrode exhibited good electrocatalytic ability to the reduction of trichloroacetic acid (TCA) with wide linear range from 1.4 to 119.4 mmol/L, low detection limit as 0.174 mmol/L (3σ), good stability and reproducibility.

Direct electrochemistry of myoglobin on TiO2 and alginate composite modified carbon ionic liquid electrode via the electrodeposition method

In this work, electrodeposition of the mixture of myoglobin (Mb), sodium alginate (SA), and TiO2 nanoparticles on the carbon ionic liquid electrode (CILE) was performed to fabricate the modified electrode which was abbreviated as Nafion/Mb-SA-TiO2/CILE. FT-IR and UV-vis absorption spectra confirmed that Mb could retain its native structure after being immobilized in the SA-TiO2 composite film. The electrochemical characterization of Nafion/Mb-SA-TiO2/CILE revealed that a pair of symmetric redox peaks appeared in the cyclic voltammograms, indicating that direct electron transfer of Mb was realized on the modified electrode. The good biocompatibility of SA, the good electrocatalytic capability of TiO2 nanoparticles, and their synergistic effects were beneficial to the electron transfer between Mb and CILE. The electrochemical parameters of the electron transfer number (n), the charge transfer coefficient (α), and the electron transfer rate constant (k s ) were calculated as 1.032, 0.402, and 0.511 s−1, respectively. The modified electrode exhibited good electrocatalytic ability to the reduction of trichloroacetic acid (TCA) and displayed wide linear range from 5.3 to 114.2 mmol/L and low detection limit as 0.152 mmol/L (3σ). The apparent Michaelis-Menten constant K M app was 32.3 mmol/L. The proposed electrode with good stability and reproducibility had the potential application in the third-generation electrochemical biosensors.

Immobilization of myoglobin on Au nanoparticle-decorated carbon nanotube/polytyramine composite as a mediator-free H2O2 and nitrite biosensor.

A novel composite film was designed for use as a highly selective mediator-free amperometric biosensor, and a method was created for accomplishing direct electrochemistry of myoglobin on a multi-walled carbon nanotube and tyramine-modified composite decorated with Au nanoparticles on a glassy carbon electrode. The ultraviolet-visible and electrochemical impedance spectroscopy results showed that myoglobin retained its native conformation in the interaction with Au-PTy-f-MWCNT. The surface coverage of Mb-heme-Fe(II)/(III) immobilized on Au-PTy-f-MWCNT and the heterogeneous electron-transfer rate constant were 2.12 × 10−9 mol cm−2 and 4.86 s−1, respectively, indicating a higher loading capacity of the nanocomposite for direct electron transfer of Mb onto the electrode surface. The proposed Mb/Au-PTy-f-MWCNT biofilm exhibited excellent electrocatalytic behavior toward the reduction of H2O2 and the oxidation of nitrite with linear ranges of 2 to 5000 μM and 1 to 8000 μM and lower detection limits of 0.01 μM and 0.002 μM, respectively. An apparent Michaelis-Menten constant of 0.12 mM indicated that the Mb immobilized on the Au-PTy-f-MWCNT film retained its native activity. This biosensor can be successfully applied to detect H2O2 and nitrite in disinfectant cream, eye drops, pickle juice, and milk samples.

Electrochemistry of myoglobin on graphene–SnO2 nanocomposite modified electrode and its electrocatalysis

In this paper direct electrochemistry and electrocatalysis of myoglobin (Mb) immobilized on a graphene (GR)–SnO2 nanocomposite modified carbon ionic liquid electrode was reported. GR–SnO2 nanocomposite was synthesized by a simple solution method and further characterized by TEM and SEM, which exhibited large surface area beneficial for Mb immobilization. Spectroscopic results indicated Mb retained its native structure without denaturation after mixed with nanocomposite. Electrochemical investigation showed that a pair of well-defined redox peaks appeared on cyclic voltammogram, indicating that direct electron transfer of Mb with the underlying electrode was realized. The results could be attributed to the presence of GR–SnO2 nanocomposite that could enhance the electron transfer between the protein and the electrode. The Mb modified electrode exhibited good stability and catalytic activity to the electroreduction of NaNO2 in the concentration range from 0.2 to 350.0μmolL−1 with wider dynamic range and lower detection limit. Therefore the fabricated electrode has the potential application in the third-generation electrochemical biosensor.

Application of three-dimensional reduced graphene oxide-gold composite modified electrode for direct electrochemistry and electrocatalysis of myoglobin.

In this paper a three-dimensional (3D) reduced graphene oxide (RGO) and gold (Au) composite was synthesized by electrodeposition and used for the electrode modification with carbon ionic liquid electrode (CILE) as the substrate electrode. Myoglobin (Mb) was further immobilized on the surface of 3D RGO-Au/CILE to obtain an electrochemical sensing platform. Direct electrochemistry of Mb on the modified electrode was investigated with a pair of well-defined redox waves appeared on cyclic voltammogram, indicating the realization of direct electron transfer of Mb with the modified electrode. The results can be ascribed to the presence of highly conductive 3D RGO-Au composite on the electrode surface that accelerate the electron transfer rate between the electroactive center of Mb and the electrode. The Mb modified electrode showed excellent electrocatalytic activity to the reduction of trichloroacetic acid in the concentration range from 0.2 to 36.0 mmol/L with the detection limit of 0.06 mmol/L (3σ).

Electrochemical method assisted immobilization and orientation of myoglobin into biomimetic brij 56 film and its direct electrochemistry study.

A simple cyclic voltammetric method was applied to assemble and orient a model protein, namely, myoglobin (Mb), into a biocompatible Brij 56 film. Ultraviolet-visible and circular dichroism spectra indicated that Mb in Brij 56 matrix preserved its secondary structure. Fourier transform infrared spectra confirmed the formation of hydrogen bonds between Mb and Brij 56. These hydrogen bonds acted as the electron tunnel to transfer electrons from Mb's active sites to the underlying glassy carbon electrode. Effective direct electron transfer of Mb was realized with the presence of a couple of quasi-reversible and well-defined redox peaks at -310 mV (vs standard calomel electrode) in the studied potential range. The peaks were attributed to the redox couple of heme Fe(II)/Fe(III) of the well-oriented Mb in Brij 56 matrix. The surface coverage and the electron transfer rate (ks) of Mb immobilized into the Brij 56 film was ∼4.9×10(-11) mol cm(-2) and 72.6±3.0 s(-1), respectively. An excellent electrocatalytic response of the immobilized Mb toward nitrite in the absence of electron transfer mediators was observed. These results emphasized that the biomimetic Brij 56 could be used as an attractive material for immobilizing proteins and constructing biosensors.

Direct electrochemistry of myoglobin at silver nanoparticles/myoglobin biocomposite: Application for hydrogen peroxide sensing

Herein we report a novel hydrogen peroxide (H2O2) sensor based on direct electrochemistry of myoglobin at a silver nanoparticles/myoglobin (Ag-NPs/MB) biocomposite modified electrode. The green synthesized Ag-NPs and MB were used for the fabrication of Ag-NPs/MB biocomposite. The fabricated Ag-NPs and Ag-NPs/MB biocomposite were characterized by using TEM and SEM respectively. A good direct electron transfer of MB is realized at Ag-NPs/MB biocomposite electrode rather than direct drop casting of MB onto Ag-NPs modified electrode, which indicates that the native structure of MB is retained in the biocomposite modified electrode. The apparent heterogenous electron transfer rate constant (ks) is calculated as 3.02s−1, which confirms a fast direct electron transfer of MB at the biocomposite electrode. A fast amperometric response for H2O2 (<5s) at Ag-NPs/MB biocomposite modified electrode indicates a good catalytic activity of the modified electrode. The H2O2 detection is found in the linear response range from 1μM to 3mM with the detection limit of 0.088μM. The sensitivity is calculated as 0.357μAμM−1cm−2. In addition, the fabricated biosensor shows a good consistency along with excellent precision.

Electrodeposited nickel oxide and graphene modified carbon ionic liquid electrode for electrochemical myglobin biosensor

By using ionic liquid 1-hexylpyridinium hexafluorophosphate based carbon ionic liquid electrode (CILE) as the substrate electrode, graphene (GR) and nickel oxide (NiO) were in situ electrodeposited step by step to get a NiO/GR nanocomposite modified CILE. Myoglobin (Mb) was further immobilized on the surface of NiO/GR/CILE with a Nafion film to get the electrochemical sensor denoted as Nafion/Mb/NiO/GR/CILE. Cyclic voltammetric experiments indicated that a pair of well-defined quasi-reversible redox peaks appeared in pH3.0 phosphate buffer solution with the formal peak potential (E0′) located at −0.188V (vs. SCE), which was the typical characteristics of Mb Fe(III)/Fe(II) redox couples. So the direct electron transfer of Mb was realized and promoted due to the presence of the NiO/GR nanocomposite on the electrode. Based on the cyclic voltammetric data, the electrochemical parameters of Mb on the modified electrode were calculated. The Mb modified electrode showed an excellent electrocatalytic activity towards the reduction of different substrates including trichloroacetic acid and H2O2. Therefore a third-generation electrochemical Mb biosensor based on NiO/GR/CILE was constructed with good stability and reproducibility.

Application of an ionic liquid-functionalized Mg2Al layered double hydroxide for the electrochemical myoglobin biosensor

In this paper, an ionic liquid 1-carboxyl-methyl-3-methylimidazolium tetrafluoroborate (CMMIMBF4)-functionalized Mg2Al layered double hydroxide (LDH) was synthesized and further used for the immobilization of myoglobin (Mb) on the surface of a carbon ionic liquid electrode to get a new electrochemical biosensor. Ultraviolet–visible and Fourier transform–infrared spectroscopies confirmed that Mb in the CMMIMBF4-LDH remained its native secondary structure, which was attributed to the biocompatibility of the materials used. On the cyclic voltammograms, a pair of well-defined redox peaks appeared, indicating that direct electron transfer of Mb was realized in the modified electrode. The formal peak potential was calculated as −0.209 V (vs. SCE), which was the typical characteristics of the Mb heme Fe(III)/Fe(II) redox couples. The fabricated Mb sensor exhibited good electrocatalytic activity to the reduction of trichloroacetic acid in the range from 1.0 to 17.0 mmol L−1 with the detection limit as 0.344 mmol L−1 (3σ), and the apparent Michaelis–Menten constant was calculated as 13.5 mmol L−1. Thus, the ionic liquid-functionalized LDH exhibited the potential application in the electrochemical sensor for redox proteins.

Fabrication of graphene–platinum nanocomposite for the direct electrochemistry and electrocatalysis of myoglobin

In this paper a platinum (Pt) nanoparticle decorated graphene (GR) nanosheet was synthesized and used for the investigation on direct electrochemistry of myoglobin (Mb). By integrating GR–Pt nanocomposite with Mb on the surface of carbon ionic liquid electrode (CILE), a new electrochemical biosensor was fabricated. UV-Vis absorption and FT-IR spectra indicated that Mb remained its native structure in the nanocomposite film. Electrochemical behaviors of Nafion/Mb–GR–Pt/CILE were investigated with a pair of well-defined redox peak appeared, which indicated that direct electron transfer of Mb was realized on the underlying electrode with the usage of the GR–Pt nanocomposite. The fabricated electrode showed good electrocatalytic activity to the reduction of trichloroacetic acid in the linear range from 0.9 to 9.0mmol/L with the detection limit as 0.32mmol/L (3σ), which showed potential application for fabricating novel electrochemical biosensors and bioelectronic devices.

Electrochemistry and electrocatalysis of myoglobin on carbon coated Fe3O4 nanospindle modified carbon ionic liquid electrode

In this paper, carbon coated Fe3O4 nanospindles (C@Fe3O4 NSs) were synthesized by partial reduction of monodispersed hematite nanospindles with carbon coatings and applied to investigate the direct electrochemistry of myoglobin (Mb). A novel modified electrode was prepared by applying carbon coated Fe3O4 nanospindles, Mb, ionic liquid (IL), 1-ethyl-3-methylimidazolium ethylsulfate ([EMIM]EtOSO3) and chitosan (CTS) step by step onto the surface of a carbon ionic liquid electrode (CILE) with another ionic liquid, 1-butyl-3-methylimidazolium tetrafluoroborate ([BMIM]BF4), as the binder. UV-Vis absorption and FT-IR spectra results indicated that Mb retained its native structure in the composite film. The electrochemical behavior of the CTS/IL/Mb/C@Fe3O4/CILE was investigated and a pair of well-defined redox peaks appeared, which indicated that the direct electron transfer of Mb was realized with the underlying electrode. The fabricated CTS/IL/Mb/C@Fe3O4/CILE showed good electrocatalytic activity in the reduction of trichloroacetic acid (TCA) with a linear range from 1.0 to 20.0 mM, which showed potential applications for fabricating novel electrochemical biosensors and bioelectronic devices.

Direct Electrochemistry and Electrocatalysis of Myoglobin with Ionic Liquid through Multilayers Film on Carbon Ionic Liquid Electrode

AbstractMultilayers of myoglobin (Mb) with ionic liquid 1‐ethyl‐3‐methylimidazolium tetrafluoroborate ([EMIM]BF4) was assembled on carbon ionic liquid electrode (CILE) based on the electrostatic attraction between the negatively charged Mb and the positively charged imidazolium ion of IL. The CILE was fabricated with 1‐ethyl‐3‐methylimidazolium ethylsulfate ([EMIM]EtOSO3) as the modifier, which exhibited imidazolium ion on the electrode surface. Then Mb molecules were assembled on the surface of CILE step‐by‐step to get a {IL/Mb}n multilayer film modified electrode. UV‐Vis adsorption and FT‐IR spectra indicated that Mb remained its native structure in the IL matrix. In deaerated phosphate buffer solution (pH 7.0) a pair of well‐defined quasi‐reversible redox peaks appeared with the apparent formal potential (E0′) as ‐0.212 V (vs. SCE), which was the characteristic of Mb heme Fe(III)/Fe(II) redox couples. The results indicated that the direct electron transfer of Mb was realized on the modified electrode. The {IL/Mb}n/CILE displayed excellent electrocatalytic ability to the trichloroacetic acid reduction in the concentration range from 2.0 to 22.0 mmol/L with the detection limit of 0.6 mmol/L (3σ). The proposed method provides a new platform to fabricate the third generation biosensor based on the self‐assembly of redox protein with ILs.

Sonochemical synthesis of magnetic core–shell Fe 3O 4@ZrO 2 nanoparticles and their application to the highly effective immobilization of myoglobin for direct electrochemistry

In this study, bifunctional Fe 3O 4@ZrO 2 magnetic core–shell nanoparticles (NPs), synthesized by a simple and effective sonochemical approach, were attached to the surface of a magnetic glassy carbon electrode (MGCE) and successfully applied to the immobilization/adsorption of myoglobin (Mb) for constructing a novel biosensor platform. With the advantages of the magnetism and the excellent biocompatibility of the Fe 3O 4@ZrO 2 NPs, Mb could be easily immobilized on the surface of the electrode in the present of external magnetic field and well retained its bioactivity, hence dramatically facilitated direct electron transfer of Mb was demonstrated. The proposed Mb/Fe 3O 4@ZrO 2 biofilm electrode exhibited excellent electrocatalytic behaviors towards the reduction of H 2O 2 with a linear range from 0.64 μM to 148 μM. This presented system avoids the complex synthesis for protecting Fe 3O 4 NPs, supplies a simple, effective and inexpensive way to immobilize protein, and is promising for construction of third-generation biosensors and other bio-magnetic induction devices.

Direct electrochemistry and electrocatalysis of myoglobin covalently immobilized in mesopores cellular foams

Myoglobin (Mb) was firstly covalently immobilized into mesopores cellular foams (MCFs) to fabricate the protein electrode (Mb–MCFs/GC electrode) and study the direct electrochemistry of redox protein. The results of UV–vis and FTIR spectra illustrated that the covalently immobilized Mb well retained its native structure and presented good stability. Cyclic voltammetry of Mb–MCFs/GC electrode showed nearly reversible cyclic voltammetric peaks, indicating the direct electron transfer of Mb–Fe III/Fe II. In addition, Mb–MCFs/GC electrode exhibited favorable electrocatalytic reduction to H 2O 2 with high sensitivity, good thermal and long-time stability. Such an avenue, which integrated mesopores cellular foams and redox protein via a simple covalent method, may provide a novel and efficient platform for the fabrication of the third generation biosensor.

Electrodeposition of Co Nanoparticles on the Carbon Ionic Liquid Electrode as a Platform for Myoglobin Electrochemical Biosensor

The electrochemical deposition of Co nanoparticles on carbon ionic liquid electrode (CILE) was described and further used as the platform to construct a myoglobin (Mb) electrochemical biosensor. CILE was prepared by mixing a certain ratio of carbon powder, 1-ethyl-3-methylimidazolium tetrafluoroborate (EMIMBF4), and liquid paraffin together. The presence of ionic liquid on the electrode surface facilitated the formation of Co nanoparticles, and a layer of Co nanoparticles was deposited on the surface of CILE with the average diameter of 300 nm after the cyclic voltammetic scan in the CoCl2 solution. The formed Co/CILE was used as a new basal electrode for the investigation on the direct electrochemistry of protein. Mb molecules were further cast on the surface of Co/CILE and immobilized with Nafion film. The fabricated Nafion/Mb/Co/CILE showed good electrochemical behaviors with a pair of well-defined quasi-reversible redox peaks of Mb obtained, which was attributed to the electrochemical reaction of heme Fe(III)/Fe(II) redox couples. The results indicated that the presence of Co nanoparticles exhibited great promotion to the direct electron transfer of Mb. The Mb electrochemical biosensor showed good electrocatalytic activity to the reduction of hydrogen peroxide and trichloroacetic acid (TCA). The modified electrodes showed good stability and reproducibility, which had potential application in third generation biosensor.

Direct electron transfer of Mb on chitosan/single-wall carbon nanotubes film modified Au electrode and its interaction with cimetidine

Three methods were used to immobilize myoglobin (Mb) on chitosan/single-wall carbon nanotubes (SWNTs) film, and direct electrochemistry of the immobilized Mb was extensively investigated. Immobilized Mb displayed a couple of stable and well-defined redox peaks with the formal potential (E’) is at about −0.27 V (vs. SCE) in 0.1 M phosphate buffer solution (pH 7.0). The E′ was shifted linearly with pH in the range of 3.0 to 9.0 with a slope of −54.1 mV pH−1, denoting that one-electron accompanies with one-proton transfer in electrode reaction process. The FT-IR spectroscopy and UV-vis spectroscopy showed that Mb on the film retained its secondary structure similar to its native state. The experimental results demonstrated that the immobilized Mb exhibited excellent electrocatalytic activity to reduction of cimetidine with a significant lowering of overpotential. The electrocatalytic current was proportional to the concentration of cimetidine over the range from 9.80 × 10−6 to 1.1 × 10−4 M; the detection limit is 8.40 × 10−6 M (signal-to-noise ratio of 3). The proposed method exhibits good sensitivity, stability and reproducibility.

Direct Electrochemistry and Bioelectrocatalysis of Myoglobin at a Carbon Nanotube-Modified Electrode

Myoglobin (Mb) was immobilized onto the surface of carbon nanotube (CNT) and was characterized by AFM, XPS, UV-Vis, and FTIR spectroscopy. The promotion effect of CNT on direct electron transfer (DET) reaction of Mb was studied. Cyclic voltammetric results showed a pair of well-defined redox peaks, which corresponded to DET of Mb, with the formal potential (E 0) of (-0.343 ± 0.001) V ( vs SCE) in the phosphate buffer solution (PBS, pH 7.0). The electrochemical parameters, such as apparent heterogeneous electron transfer rate constant ( k s) and E 0, were determined. The dependence of E0' on solution pH indicated that DET reaction of Mb was coupled with proton transfer. The experimental results also demonstrated that the immobilized Mb retained its bioelectrocatalytic activity toward the reduction of H 2O 2 and O 2.

Gold nanoparticle-attached ITO as a biocompatible matrix for myoglobin immobilization: direct electrochemistry and catalysis to hydrogen peroxide

A gold nanoparticle-attached indium tin oxide (Au/ITO) electrode was applied for myoglobin (Mb) immobilization. The direct electron transfer of Mb was shown by the stable and well-behaved voltammetric responses for Mb immobilized on the Au/ITO electrode in buffer solutions. The effects of scan rate, pH value and oxygen on the direct electrochemistry of Mb were observed. Based on the catalytic activity of Mb immobilized on a gold nanoparticle-modified ITO (Mb/Au/ITO) electrode toward the reduction of H 2O 2, a mediator-free H 2O 2 sensor was developed, which showed good reproducibility and stability in pH 7.0 buffer. A linear relationship existed between the catalytic current and the H 2O 2 concentration in the range of 2.5 × 10 −6–5 × 10 −4 M with a detection limit ( S/ N = 3) of 4.8 × 10 −7 M.