Direct Electron Transfer Of Hemoglobin Research Articles

Direct electrochemistry of covalently immobilized hemoglobin on a naphthylimidazolium butyric acid ionic liquid/MWCNT matrix

Monitoring the concentration levels of hydrogen peroxide (H2O2) is significant in both clinical and industrial applications. Herein, we develop a facile biosensor for the detection of H2O2 based on direct electron transfer of hemoglobin (Hb), which was covalently immobilized on a hydrophobic naphthylimidazolium butyric acid ionic liquid (NIBA-IL) over a multiwalled carbon nanotube (MWCNT) modified glassy carbon electrode (GCE) to obtain an Hb/NIBA-IL/MWCNT/GCE. Highly water-soluble Hb protein was firmly immobilized on NIBA-IL via stable amide bonding between the free NH2 groups of Hb and COOH groups of NIBA-IL via EDC/NHS coupling. Thus fabricated biosensor showed a well resolved redox peak with a cathodic peak potential (Epc) at −0.35 V and anodic peak potential (Epa) at −0.29 V with a formal potential (E°’) of −0.32 V, which corresponds to the deeply buried FeIII/FeII redox centre of Hb, thereby direct electrochemistry of Hb was established. Further, the modified electrode demonstrated very good electrocatalytic activity towards H2O2 reduction and showed a wide linear range of detection from 0.01 to 6.3 mM with a limit of detection and sensitivity of 3.2 μM and 111 μA mM−1 cm−2, respectively. Moreover, the developed biosensor displayed high operational stability under dynamic conditions as well as during continuous potential cycles and showed reliable reproducibility. The superior performance of the fabricated biosensor is attributed to the effective covalent immobilization of Hb on the newly developed highly conducting and biocompatible NIBA-IL/MWCNT/GCE platform.

Bioelectrocatalysis of Hemoglobin on Electrodeposited Ag Nanoflowers toward H2O2 Detection.

Hydrogen peroxide (H2O2) is a partially reduced metabolite of oxygen that exerts a diverse array of physiological and pathological activities in living organisms. Therefore, the accurate quantitative determination of H2O2 is crucial in clinical diagnostics, the food industry, and environmental monitoring. Herein we report the electrosynthesis of silver nanoflowers (AgNFs) on indium tin oxide (ITO) electrodes for direct electron transfer of hemoglobin (Hb) toward the selective quantification of H2O2. After well-ordered and fully-grown AgNFs were created on an ITO substrate by electrodeposition, their morphological and optical properties were analyzed with scanning electron microscopy and UV–Vis spectroscopy. Hb was immobilized on 3-mercaptopropionic acid-coated AgNFs through carbodiimide cross-linking to form an Hb/AgNF/ITO biosensor. Electrochemical measurement and analysis demonstrated that Hb retained its direct electron transfer and electrocatalytic properties and acted as a H2O2 sensor with a detection limit of 0.12 µM and a linear detection range of 0.2 to 3.4 mM in phosphate-buffered saline (PBS). The sensitivity, detection limit, and detection range of the Hb/AgNF/ITO biosensor toward detection H2O2 in human serum was also found to be 0.730 mA mM−1 cm−2, 90 µM, and 0.2 to 2.6 mM, indicating the clinical application for the H2O2 detection of the Hb/AgNF/ITO biosensor. Moreover, interference experiments revealed that the Hb/AgNF/ITO sensor displayed excellent selectivity for H2O2.

Direct electron transfer of hemoglobin at 3D graphene–nitrogen doped carbon nanotubes network modified electrode and electrocatalysis toward nitromethane

In this work, pulsed potentiostatic reduction method was presented to directly construct a three dimensional graphene‑nitrogen doped carbon nanotubes (3DG-NCNTs) network on the surface of a glassy carbon electrode (GCE). Scanning electron microscopy (SEM), Raman spectra and electrochemical experiments revealed the characteristics of the 3DG-NCNTs network. Further, such 3DG-NCNTs network was employed to immobilize a model molecule, hemoglobin (Hb), for the construction of an electrochemical nitromethane (CH3NO2) biosensor. The electrochemical properties of the biosensor were studied in detail, including the direct electron transfer of Hb and the electrochemical determination of CH3NO2. Due to the 3DG-NCNTs network, electrochemical biosensor demonstrated fast electron transfer rate (7.12 s−1) and excellent catalytic activity toward CH3NO2. Under optimal conditions, the proposed biosensor exhibited a wide linear response in the range of 5.0 × 10−7–3.5 × 10−4 mol L−1, with a low detection limit of 1.5 × 10−7 mol L−1. In addition, the biosensor had high reproducibility, stability and selectivity, which provided the possibility for the monitoring of CH3NO2 in real samples.

Direct electron transfer of hemoglobin at nitrogen incorporated reduced graphene oxide obtained by radio frequency ammonia plasma treatment

We report a facile strategy to prepare nitrogen functionalized reduced graphene oxide (NRGO) by using ammonia plasma treatment of reduced graphene oxide (RGO) synthesized via a chemical method. The chemical composition of NRGO and its morphology was studied extensively by various surface probing techniques such as Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, transmission electron microscopy and Raman spectroscopy. Electrochemical investigations were performed using various redox probes such as potassium ferricyanide and hexaammineruthenium (III) chloride indicated a large electroactive surface area of NRGO and fast electron transfer. Meanwhile the direct electron transfer of hemoglobin (Hb) immobilized on NRGO was confirmed by a reduction peak that appeared on the cyclic voltammogram. Further, the electron transfer coefficient (α) and heterogeneous electron transfer rate constant (ks) for Hb at the NRGO were calculated to be 0.43 and 1.05s−1 respectively. Moreover, the GCE/NRGO/Hb modified electrode was employed for the determination of nitrite over the linear range from 5 to 300nM with a limit of detection of 1.3nM. Our results suggest that NRGO is a potential candidate for the electrochemical sensing of nitrite.

Direct Electron Transfer of Hemoglobin on Indium-Tin Oxide Electrodes Synthesized By Dip-Coating Methods Under Different Sintering Temperature

The direct electron transfer (DET) between electrodes and redox proteins is important when considering practical applications such as body implantable devices for cardiac resynchronization therapy (CRT) and deep brain stimulation (DBS), since such electrical devices should require biocompatibility, simplicity of electrodes, potential difference in electrochemical cells, etc. We have investigated the DET properties of hemoglobin (Hb) molecules on indium-tin-oxide (ITO) electrodes [1-3]. In our previous study, the ITO electrodes were synthesized on glass plates by using dip-coating solution with different Sn/(Sn+In) molar ratio, and Hb molecules showed the DET activity on the synthesized ITO electrodes [3]. It was found that the DET activities of Hb molecules were different at ITO electrodes synthesized from different Sn ratio. The largest DET current was observed on the ITO electrode synthesized from a Sn ratio of 0.50. The results also suggested from previous studies with different Sn ratio that the active sites and electrical properties of ITO might be related with the DET behavior with Hb molecules. To understand the relationship between crystallinity of ITO and DET of Hb molecules on electrode surfaces, in this study, ITO electrodes were prepared on quartz plates under different sintering temperature from 350°C to 950°C for 15 min by using dip-coating solution with the Sn ratio of 0.50. The coating procedure was repeated ten times. X-ray diffraction (XRD) peaks attributed to Sn-doped In2O3 were observed, with the peak intensity increasing with increasing sintering temperature. Cyclic voltammetry (CV) was conducted with a three-electrode system in 39 mM phosphate buffered saline (PBS; pH 7.4) with or without 100 μM Hb solution. ITO sintered at 350°C and 950°C behaved as poor electrodes due to their high electrical resistance. Hb molecules showed good DET activities on the ITO electrodes sintered at 500°C, 650°C, and 800°C. The results indicated that there were optimum crystallinity of the ITO electrodes for showing DET activity to Hb molecules.

A novel nitrite biosensor based on direct electron transfer of hemoglobin immobilized on a graphene oxide/Au nanoparticles/multiwalled carbon nanotubes nanocomposite film

Download options Please wait... Article information DOI https://doi.org/10.1039/C4RA05237D Article type Paper Submitted 02 Jun 2014 Accepted 14 Jul 2014 First published 15 Jul 2014 Download Citation RSC Adv., 2014,4, 31573-31580 BibTex EndNote MEDLINE ProCite ReferenceManager RefWorks RIS Permissions Request permissions A novel nitrite biosensor based on direct electron transfer of hemoglobin immobilized on a graphene oxide/Au nanoparticles/multiwalled carbon nanotubes nanocomposite film Y. Wang and C. Bi, RSC Adv., 2014, 4, 31573 DOI: 10.1039/C4RA05237D To request permission to reproduce material from this article, please go to the Copyright Clearance Center request page. If you are an author contributing to an RSC publication, you do not need to request permission provided correct acknowledgement is given. If you are the author of this article, you do not need to request permission to reproduce figures and diagrams provided correct acknowledgement is given. If you want to reproduce the whole article in a third-party publication (excluding your thesis/dissertation for which permission is not required) please go to the Copyright Clearance Center request page. Read more about how to correctly acknowledge RSC content. Social activity Tweet Share Search articles by author Yan Wang Chun-yan Bi

PANI–TiC nanocomposite film for the direct electron transfer of hemoglobin and its application for biosensing

A novel polyaniline and titanium carbide (PANI–TiC) nanocomposite was synthesized by an in situ chemical oxidative polymerization method, and a hydrogen peroxide (H2O2) biosensor was fabricated by PANI–TiC with hemoglobin (Hb)-modified glassy carbon electrode (GCE). Scanning electron microscope and energy dispersive X-ray spectroscopy showed the morphology and ingredient of PANI–TiC. Electrochemical investigation of the biosensor showed a pair of well-defined, quasi-reversible redox peaks with E pa = −0.318 V and E pc = −0.356 V (vs SCE) in 0.1 M, pH 7.0 sodium phosphate-buffered saline at the scan rate of 150 mV s−1. Transfer rate constant (k s) was 2.01 s−1. The Hb/PANI–TiC/GCE showed a good electrochemical catalytic response for the reduction of H2O2 with the linear range from 0.5 to 285.5 μM and the detection limit of 0.2 μM (S/N = 3). The apparent Michaelis–Menten constant (K m) was estimated to be 1.21 μM. Therefore, the PANI–TiC as a novel matrix opened up a further possibility for study on the design of enzymatic biosensors with potential applications.

Direct electron transfer of hemoglobin intercalated in exfoliated Ni–Al–CO3 layered double hydroxide and its electrocatalysis towards hydrogen peroxide

In this study, hemoglobin (Hb) was entrapped into the exfoliated Ni–Al–CO3 layered double hydroxides (LDH).

Direct Electrochemistry of Hemoglobin Immobilized on a Functionalized Multi-Walled Carbon Nanotubes and Gold Nanoparticles Nanocomplex-Modified Glassy Carbon Electrode

Direct electron transfer of hemoglobin (Hb) was realized by immobilizing Hb on a carboxyl functionalized multi-walled carbon nanotubes (FMWCNTs) and gold nanoparticles (AuNPs) nanocomplex-modified glassy carbon electrode. The ultraviolet-visible absorption spectrometry (UV-Vis), transmission electron microscopy (TEM) and Fourier transform infrared (FTIR) methods were utilized for additional characterization of the AuNPs and FMWCNTs. The cyclic voltammogram of the modified electrode has a pair of well-defined quasi-reversible redox peaks with a formal potential of −0.270 ± 0.002 V (vs. Ag/AgCl) at a scan rate of 0.05 V/s. The heterogeneous electron transfer constant (ks) was evaluated to be 4.0 ± 0.2 s−1. The average surface concentration of electro-active Hb on the surface of the modified glassy carbon electrode was calculated to be 6.8 ± 0.3 × 10−10 mol cm−2. The cathodic peak current of the modified electrode increased linearly with increasing concentration of hydrogen peroxide (from 0.05 nM to 1 nM) with a detection limit of 0.05 ± 0.01 nM. The apparent Michaelis-Menten constant (Kmapp) was calculated to be 0.85 ± 0.1 nM. Thus, the modified electrode could be applied as a third generation biosensor with high sensitivity, long-term stability and low detection limit.

A Nitrite Biosensor Based on the Direct Electron Transfer of Hemoglobin Immobilized on Carboxyl‐Functionalized Multiwalled Carbon Nanotubes/Polyimide Composite

AbstractThe high electrically conductive carboxyl‐functionalized multiwalled carbon nanotubes (COOH‐MWCNTs) were used to combine with nonconducting polyimide (PI) to generate a PI/COOH‐MWCNTs membrane. PI served as a matrix to entrap COOH‐MWCNTs and hemoglobin (Hb). COOH‐MWCNTs can improve the conductivity of the composite. The direct electrochemistry measurement indicated that the PI/COOH‐MWCNTs composite enhanced the immobilization of Hb significantly. Besides, the Hb/PI/COOH‐MWCNTs/GCE biosensor possessed excellent electrocatalytic activity for the detection of nitrite. Therefore, PI is a good matrix for Hb immobilization and it has application in sensor construction. This work is promising in the development of sensitive biosensors based on PI/COOH‐MWCNTs composite film.

A hydrogen peroxide biosensor based on the direct electron transfer of hemoglobin in the nanosheets of exfoliated HNb3O8

In the present work, hemoglobin (Hb) was entrapped into the nanosheets of a pre-exfoliated layered material HNb3O8. UV–vis spectra analysis displayed that no significant denaturation occurred to the entrapped protein. Electrochemical results showed that the entrapment of Hb into layered HNb3O8 enhanced the direct electron transfer ability between protein molecules and electrode. A pair of well-defined redox peaks was observed at −0.39 and −0.34 V on the glassy carbon electrode modified with the Hb/HNb3O8 composite. The electrode reactions showed a surface-controlled process with a single electron transfer at the scan rate of 50–400 mV/s, and the electron transfer rate was very fast. The entrapped Hb retained its biological activity well and the sensor constructed by the Hb/HNb3O8-composite-modified electrode displayed excellent response to the reduction of hydrogen peroxide (H2O2) with wide linear range, low detection limit, and good stability.

Application of NiMoO4 Nanorods for the Direct Electrochemistry and Electrocatalysis of Hemoglobin with Carbon Ionic Liquid Electrode

AbstractIn this paper NiMoO4 nanorods were synthesized and used to accelerate the direct electron transfer of hemoglobin (Hb). By using an ionic liquid (IL) 1‐butylpyridinium hexafluorophosphate (BPPF6) modified carbon paste electrode (CILE) as the basic electrode, NiMoO4 nanorods and Hb composite biomaterial was further cast on the surface of CILE and fixed by chitosan (CTS) to establish a modified electrode denoted as CTS/NiMoO4‐Hb/CILE. UV‐vis and FT‐IR spectroscopic results showed that Hb in the film retained its native structures without any conformational changes. Electrochemical behaviors of Hb entrapped in the film were carefully investigated by cyclic voltammetry with a pair of well‐defined and quasi‐reversible redox voltammetric peaks appearing in phosphate buffer solution (PBS, pH 3.0), which was attributed to the direct electrochemistry of the electroactive center of Hb heme Fe(III)/Fe(II). The results were ascribed to the specific characteristic of NiMoO4 nanorods, which accelerated the direct electron transfer rate of Hb with the underlying CILE. The electrochemical parameters of Hb in the composite film were further carefully calculated with the results of the electron transfer number (n) as 1.08, the charge transfer coefficient (α) as 0.39 and the electron‐transfer rate constant (ks) as 0.82 s−1. The Hb modified electrode showed good electrocatalytic ability toward the reduction of trichloroacetic acid (TCA) in the concentration range from 0.2 to 26.0 mmol/L with a detection limit of 0.072 mmol/L (3σ), and H2O2 in the concentration range from 0.1 to 426.0 µmol/L with a detection limit of 3.16×10−8 mol/L (3σ).

Direct electron transfer of hemoglobin in a biocompatible electrochemical system based on zirconium dioxide nanotubes and ionic liquid

Highly-ordered zirconium dioxide (ZrO 2) nanotubes were prepared with porous anodic alumina as the template by the liquid phase deposition technique. The obtained ZrO 2 nanotubes were characterized by transmission electron micrograph (TEM) and X-ray diffraction (XRD). A new biocompatible nano-platform for the immobilization of hemoglobin (Hb) was developed by coating a chitosan (CHI) solution, in which the ZrO 2 nanotubes, 1-butyl-3-methylimidazolium tetrafluoroborate ionic liquid ([BMIM]BF 4) and Hb were dispersed, onto a glassy carbon electrode surface. Direct electrochemistry of the immobilized Hb on the electrode surface was then investigated. The results indicated that remarkable improvements on the direct electrochemistry of Hb were achieved. In addition, the potential application of the Hb immobilized electrode (Hb/ZrO 2/[BMIM]BF 4/CHI/GCE) in biosensing was demonstrated by the catalytic electrochemical reduction of nitrite ion (NO 2 −) in an aqueous solution.

Direct electron transfer of hemoglobin on nickel oxide nanoparticles modified graphite electrode

Direct electron transfer of hemoglobin, immobilized on a nickel oxide nanoparticles modified graphite electrode, was studied. Nickel oxide nanoparticles synthesized by electrochemical methods. The prepared nanoparticles were characterized by scanning electron microscope (SEM) and transmission electron microscope (TEM). The resulting electrode displayed an excellent redox behavior for the hemoglobin. The hemoglobin showed a quasi-reversible electrochemical redox behavior with a formal potential of -48±5 mV (versus Ag/AgCl) in 50 mM potassium phosphate buffer solution at pH 7.0 and temperature 25°C. The cathodic transfer coefficient was 0.45 and electron transfer rate constant was evaluated to be 1.95 s−1. Furthermore, the modified electrode was used as a biosensor and exhibited a satisfactory stability and sensitivity to H2O2. The linear range of this biosensor for H2O2 determination was from 15 to 650 µM while standard deviation in 40 µM H2O2 concentration was 2.8% for 4 repetitions. Key words: Electron transfer, hemoglobin, nickel oxide, nanoparticles, biosensor.

Direct Electron Transfer of Hemoglobin and Myoglobin at the Bare Glassy Carbon Electrode in an Aqueous BMI.BF4 Ionic‐Liquid Mixture

Direct and remarkably fast electron transfers between a bare glassy carbon electrode and heme proteins (hemoglobin or myoglobin) are obtained by using an aqueous 1-butyl-3-methyl imidazolium tetrafluoroborate (BMI.BF(4)) ionic-liquid mixture as electrolyte. The ionic liquid is observed to play a key role in the achievement of the electron transfer. The experimental data show that the proteins are not strongly adsorbed onto the electrode surface while giving rise to sharp and well-defined redox responses. Such a finding contrasts with most of the reported works found in literature and-beyond the fundamental aspect--it may be of interest in applications where adsorption is critical. Moreover, the electrocatalytic activity of the proteins toward the reduction of oxygen and nitrite in the aqueous BMI.BF(4) mixture is evidenced, showing the potential of this simple approach for bioelectroanalytical devices.

A hydrogen peroxide biosensor based on the direct electron transfer of hemoglobin encapsulated in liquid-crystalline cubic phase on electrode

Liquid crystal cubic phase formed with monoolein has been used as immobilizing matrix to host redox protein hemoglobin on glassy carbon electrode surface. The promoted direct electron transfer between hemoglobin and electrode was observed and a large average kinetic electron transfer rate constant k s of 3.03(±0.02) s −1 was estimated. The electrode modified with cubic phase containing hemoglobin retains the bioactivity of hemoglobin and shows excellent bioelectrocatalytic activity to the reduction of hydrogen peroxide with a small apparent Michaelis–Menten constant of 0.25(±0.03) mM. A novel reagentless hydrogen peroxide biosensor was constructed using the hemoglobin-containing cubic phase modified electrode and the proposed hydrogen peroxide biosensor shows a linear range of 7.0–239 μM with a detection limit of 3.1(±0.2) μM and good stability and reproducibility.

Direct Electron Transfer of Hemoglobin in a Hydrophilic Ionic Liquid/Gellan Gum Composite Film Modified Carbon Ionic Liquid Electrode

AbstractA gellan gum (GG)‐Hemoglobin (Hb)‐1‐butyl‐3‐methyl‐imidazolium tetrafluoroborate ([BMIM] [BF4])/carbon ionic liquid electrode(CILE), GG‐Hb‐[BMIM][BF4]/CILE, was fabricated, and the direct electron transfer of hemoglobin and electrocatalytic reaction for electrocatalytic abilities were carefully investigated. Scanning electron microscopy images of the modified electrode showed that it had a dendritic structure. UV‐Vis spectra and FT‐IR spectra showed that Hb in the composite film retained its native structure. Cyclic voltammogram of the modified electrode showed that a pair of well‐defined redox peaks of Hb is observed with the formal potential (E0) of −0.278 V (vs. SCE). The electron transfer coefficient (a) and the apparent heterogeneous electron transfer rate constant (ks) was 0.44 and 2.0 s−1, respectively. The modified electrode also exhibited excellent electrocatalytic ability to the reduction of trichloroacetic acid and hydrogen peroxide with a detection limit of 6.8 μmol/L and 1.5 μmol/L (S/N = 3), respectively. The apparent Michaelis‐Menten constant (KMapp) was estimated to be 4.3 mmol/L and 0.13 mmol/L, respectively. The present study proved that the combination of GG‐[BMIM][BF4] film with CILE is able to open up new opportunities for the design of enzymatic biosensors with potential applications in practice.

Ag nanoparticles self-supported on Ag 2V 4O 11 nanobelts: Novel nanocomposite for direct electron transfer of hemoglobin and detection of H 2O 2

Nanocomposite of Ag nanoparticles self-supproted on Ag 2V 4O 11 nanobelts, prepared by γ-ray irradiation treatments of Ag 2V 4O 11 nanobelts, was used to immobilize hemoglobin on glassy carbon electrode. Detailed electrochemical analysis was performed and it was found that Ag/Ag 2V 4O 11 nanocomposite significantly improved the direct electron transfer between hemoglobin and glassy carbon electrode, leading to the fabrication of a biosensor with a very sensitive detection of H 2O 2. The apparent surface concentration ( Γ*) of hemoglobin and the electron transfer rate constant ( k s) were calculated to be 1.6 × 10 −10 mol/cm 2 and 2.6 s −1, respectively. The linear detection range of H 2O 2 was 1.0–120 μM, with a detection limit of 0.3 μM.

Effects of pore structure of mesoporous silicas on the electrochemical properties of hemoglobin

Effects of pore structure of mesoporous silicas (MPS) on the direct electron transfer of hemoglobin (Hb) were investigated. MCM-41 and SBA-15 were used to supply 1D channel and hexagonal mesoporous structure with the average pore diameters of 3.2 and 6.9 nm, respectively, while MCF was used to supply 3D and caged mesoporous network structure with the average pore diameter of 15.7 nm. Hb was immobilized by the physical adsorption method without significant denaturation and have the saturated binding amounts of 15.8, 240.0 and 325.7 mg g −1 for MCM-41, SBA-15 and MCF, respectively. The electrochemical properties of Hb/MPS/GC modified electrode were studied by cyclic voltammetry (CV). A couple of redox peaks were observed at Hb/SBA-15/GC and Hb/MCF/GC, while no obvious redox peak was found at Hb/MCM-41/GC modified electrode because Hb molecule could not enter into the channels of MCM-41. The CV signal of Hb/MCF/GC is about 2× as large as that of Hb/SBA-15/GC electrode when the same amount of Hb was immobilized in the pores of MCF and SBA-15, which suggests that the 3D porous structure may be the key factor for promoting the electron transfer of Hb.

Direct Electron Transfer and Enhanced Electrocatalytic Activity of Hemoglobin at Iron-Rich Clay Modified Electrodes

The possible role of structural iron in clays to promote direct electron transfer of hemoglobin (Hb) was investigated. Clays containing different amounts of iron situated in octahedral or tetrahedral sites have been used to modify glassy carbon electrodes: nontronite, synthetic montmorillonite, and saponite. A synthetic montmorillonite containing non-iron impurities was used as a reference. Interactions between Hb and these clays were studied with the establishment of adsorption isotherms and by the analysis of X-ray diffraction patterns, FTIR, and UV-vis spectra of the Hb-clay samples. The electrochemical behavior of clay modified electrodes (CME) was characterized by cyclic voltammetry in the presence of Hb in solution or adsorbed within the clays. Nontronite, which contains the highest amount of structural iron, enhanced significantly direct electron transfer of Hb. Finally, the electrocatalytic behavior of Hb-Nontronite CME in the presence of hydrogen peroxide was also studied, and the H(2)O(2) calibration curve was recorded under amperometric conditions for different bioelectrode configurations.