Direct Electron Transfer Of Hemoglobin Research Articles

Fabrication, characterization of Fe 3O 4 multilayer film and its application in promoting direct electron transfer of hemoglobin

Fe 3O 4 magnetic multilayer films were constructed on several conductive bases (glassy carbon electrode, ITO glass and Al foil) by the firstly electrodeposited chitosan/Fe 3O 4 nanoparticles thin film and then the layer-by-layer assembly using phytic acid and Fe 3O 4/chitosan. Scanning electronic microscopy (SEM), UV–vis spectra, electrochemical impedance spectroscopy (EIS) and superconducting quantum interference device (SQUID) measurements were used to characterize the multilayer films. Characteristic superparamagnetic properties of Fe 3O 4 nanoparticles are well remained in the film and could be controlled simply by changing the assembly layers. Moreover, the multilayer film showed good biocompatibility, the adsorbed hemoglobin (Hb) on the film realized direct electron transfer with the underlying GCE and kept high catalytic activity. This presented system avoid the complex synthesis for protecting Fe 3O 4 nanoparticles, and supplies a simple, universal way to construct other nanoparticles films on many conductive bases for biosensors’ development.

Synergistic effect of zirconium phosphate and Au nanoparticles on direct electron transfer of hemoglobin on glassy carbon electrode

The direct electron transfer of hemoglobin (Hb) was successfully realized on Au–zirconium phosphate nanocomposite (Au–ZrP) modified glassy carbon electrode (GCE) based on the synergistic effect between ZrP and Au nanoparticles. The interaction between Hb and Au–ZrP was studied by UV–Vis spectroscopy, electrochemical impedance spectroscopy, and cyclic voltammetry. A couple of stable and well-defined redox peaks of Hb immobilized on Au–ZrP was observed at about −134 and 35 mV in pH 6.0 buffers. Moreover, the immobilized Hb showed excellent electrocatalysis to the reduction of H 2O 2, which was used to construct H 2O 2 sensors. The obtained sensor could determine H 2O 2 from 15 μmol l −1 to 0.48 mmol l −1 with detection limit of 7.4 μmol l −1( S/ N = 3). Its apparent Michaelis–Menten constant, K app M , was 0.65 mmol l −1.

Direct electron transfer of hemoglobin on PSS/SWNTs film modified Au electrode and its interaction with ribavirin

Direct electrochemistry of hemoglobin (Hb) immobilized on the PSS/SWNTs film modified Au electrode was studied. The immobilized Hb displayed a couple of stable and well-defined redox peaks with the formal potential ( E 0′) of about 0.117 V (versus SCE) in a 0.1 M phosphate buffer solution (PBS) of pH 7.0. The dependence of E 0′ on the solution pH indicated that the direct electron transfer reaction of Hb was that the electrons transfer was accompanied by an equal number of protons in reaction process. Both single-wall carbon nanotubes (SWNTs) and poly(styrene sulfonic acid) sodium salt (PSS) could accelerate the electron transfer between Hb and the electrode. Using the PSS/Hb/SWNTs film modified Au electrode, the interaction between Hb and ribavirin was studied.

A hydrogen peroxide biosensor based on Langmuir–Blodgett technique: Direct electron transfer of hemoglobin in octadecylamine layer

The present paper describes the modification of hemoglobin (Hb)–octadecylamine (ODA) Langmuir–Blodgett (LB) film on a gold electrode surface to develop a novel electrochemical biosensor for the detection of hydrogen peroxide. Atomic force microscopy (AFM) image of Hb–ODA LB film indicated Hb molecules existed in ODA layer in a well-ordered and compact form. The immobilized Hb displayed a couple of stable and well-defined redox peaks with an electron transfer rate constant of 4.58 ± 0.95 s −1 and a formal potential of −185 mV (versus Ag/AgCl) in phosphate buffer (1.0 mM, pH 5.0) contain 0.1 M KCl at a scan rate of 200 mV s −1, characteristic of Hb heme Fe(III)/Fe(II) redox couple. The formal potential of Hb heme Fe(III)/Fe(II) redox couple in ODA film shifted linearly between pH 5 and 8 with a slope of −23.8 mV pH −1, suggesting that proton took part in electrochemical reaction. The ODA could accelerate the electron transfer between Hb and the electrode. This modified electrode showed an electrochemical activity to the reduction of hydrogen peroxide (H 2O 2) without the aid of any electron mediator.

Direct electron transfer and bioelectrocatalysis of hemoglobin at a carbon nanotube electrode

A stable suspension of carbon nanotube (CNT) can be obtained by dispersing the CNT in the solution of the surfactant cetyltrimethylammonium bromide. CNT has promotion effects on the direct electron transfer of hemoglobin (Hb), which was immobilized onto the surface of CNT. The direct electron transfer rate of Hb was greatly enhanced after it was immobilized onto the surface of CNT. Cyclic voltammetric results showed a pair of well-defined redox peaks, which corresponded to the direct electron transfer of Hb, with the formal potential ( E 0 ′ ) at about −0.343 V (vs. saturated calomel electrode) in the phosphate buffer solution (pH 6.8). The electrochemical parameters such as apparent heterogeneous electron transfer rate constant ( k s) and the value of formal potential ( E 0 ′ ) were estimated. The dependence of E 0 ′ on solution pH indicated that the direct electron transfer reaction of Hb is a one-electron transfer coupled with a one-proton transfer reaction process. The experimental results also demonstrated that the immobilized Hb retained its bioelectrocatalytic activity to the reduction of H 2O 2. The electrocatalytic current was proportional to the concentration of H 2O 2 at least up to 20 mM.

A nitric oxide biosensor based on the multi-assembly of hemoglobin/montmorillonite/polyvinyl alcohol at a pyrolytic graphite electrode

Direct electron transfer of hemoglobin (Hb) can be achieved in a Hb/montmorillonite (MMT)/polyvinyl alcohol multi-assembly at a pyrolytic graphite (PG) electrode. Accordingly, a novel nitric oxide (NO) biosensor is proposed. The reduction of NO is observed at a potential of approximately −783 mV (vs. SCE) at pH 5.5. At optimum pH, this biosensor shows a wide linear range of 1.0×10 −6–2.5×10 −4 mol/l with a detection limit of 5.0×10 −7 mol/l. The sensor-to-sensor reproducibility is good considering̱ a relative standard deviation of 3.5% in five independent determinations at 5.0×10 −5 mol/l NO. The modified electrode is conveniently constructed and durable in long-term operations.

Nitrite reduction and detection at a carbon paste electrode containing hemoglobin and colloidal gold.

A novel renewable reagentless nitrite biosensor based on the direct electron transfer of hemoglobin (Hb) and a new sensing mechanism was proposed by combining the advantageous features of colloidal gold nanoparticle and carbon paste technology. The direct electrochemistry of immobilized Hb displayed a pair of redox peaks with a formal potential of -42 mV (vs. NHE) in 0.2 mol dm(-3) NaAc-HAc buffer (pH 5.5). The immobilized Hb displayed an excellent response to the reduction of NO2(-) with one interfacial charge transfer followed by a chemical reaction (EC) mechanism. Under optimal conditions, the interfacial EC process could be used for the sensitive determination of NO2(-) with a linear range from 0.1 to 9.7 micromol dm(-3) and a detection limit of 0.06 [micro sign]mol dm(-3) at 3sigma. The amperometric determination of high concentrations of NO2(-) based on the irreversible reduction of NO could be performed at pH 4.0 with a linear range from 0.1 to 1.2 mmol dm(-3). The surface of biosensor could be renewed quickly and reproducibly by a simple polish step. The biosensor has been used satisfactorily for nitrite determination in native water samples.