Electrochemical and spectroelectrochemical characterization of different mesoporous TiO2 film electrodes for the immobilization of Cytochrome c (original) (raw)
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Interfacial electron transfer on cytochrome-c sensitised conformally coated mesoporous TiO2 films
Bioelectrochemistry, 2008
Hybrid protein films incorporating Cyt-c immobilized on TiO 2 films were prepared and characterised optically with UV-visible spectroscopy and electrochemically with cyclic voltammetry, and their conductivity properties were studied in detail. In addition the effects of a thin overlayer coating of a second metal oxide such as SiO 2 , Al 2 O 3 , ZrO 2 and MgO 2 were studied and the effects over the electrochemical properties of the hybrid working electrodes were discussed.
Langmuir, 2020
Enhancing the molecular interaction is critical for improving the 17 immobilization and stability of protein on TiO 2 surfaces. In this work, mesoporous TiO 2 18 materials with varied pore geometries were decorated with phenyl phosphoric acid 19 (PPA), followed by a thermal treatment to obtain chemically heterogeneous C-TiO 2 20 samples without changing the geometry and crystalline structure, which can keep the 21 advantages of both carbon and TiO 2. The molecular interaction force between the 22 protein and the surfaces was measured using the atomic force microscopy (AFM) by 23 decomposing from the total adhesion forces, showing that the surface chemistry 24 determines the interaction strength and depends on the amount of partial carbon 25 coverage on the TiO 2 surface (~40%-80%). Samples with 58.3 % carbon coverage 26 provide the strongest molecular interaction force, consistent with the observation from 27 the detected friction force. Surface-enhanced Raman scattering (SERS) and 28 electrochemical biosensor measurements for these C-TiO 2 materials were further 29 conducted to illustrate their practical implications, implying their promising 30 applications such as protein detection and biosensors.
Journal of Nanobiotechnology, 2011
Background: For bioanalytical systems sensitivity and biomolecule activity are critical issues. The immobilization of proteins into multilayer systems by the layer-by-layer deposition has become one of the favorite methods with this respect. Moreover, the combination of nanoparticles with biomolecules on electrodes is a matter of particular interest since several examples with high activities and direct electron transfer have been found. Our study describes the investigation on silica nanoparticles and the redox protein cytochrome c for the construction of electro-active multilayer architectures, and the electron transfer within such systems. The novelty of this work is the construction of such artificial architectures with a non-conducting building block. Furthermore a detailed study of the size influence of silica nanoparticles is performed with regard to formation and electrochemical behavior of these systems.
Electrochemistry of Nanozeolite-Immobilized Cytochrome c in Aqueous and Nonaqueous Solutions
Langmuir, 2010
The electrochemical properties of cytochrome c (cyt c) immobilized on multilayer nanozeolite modified electrodes have been examined in aqueous and nonaqueous solutions. Layers of Linde type-L zeolites were assembled on indium tin oxide (ITO) glass electrodes followed by adsorption of cyt c, primarily via electrostatic interactions, onto the modified ITO electrodes. The heme protein displayed a quasireversible response in aqueous solution with a redox potential of +324 mV (vs NHE), the surface coverage ( * ) increased linearly for the first four layers and then gave a nearly constant value of 200 pmol cm 2-. On immersion of the modified electrodes in 95% (v/v) nonaqueous solutions, the redox potential decreased significantly, a decrease that originated from changes in both the enthalpy and entropy of reduction. On re-immersion of the modified electrode in buffer, the faradic response immediately returned to its original value. These results demonstrate that nanozeolites have potential as stable supports for redox proteins and enzymes.
2013
In this thesis, the research work was focused on the immobilization of different enzymes (oxidases and dehydrogenases) into biocomposite silica matrix with the aim of amperometric biosensors construction. Then, the structured nanomaterials were introduced in the system in order to improve the characteristics of biosensors. The method of electrochemically-assisted deposition was chosen for the immobilization of enzymes on the surface of nanomaterials as it provides possibility of fine tuning of film thickness allowing covering each individual nanoobject. The feasibility of this was shown while modifying the platinum nanofibers, which demonstrate high electroactive surface and H2O2 oxidation rate, with silica-glucose oxidase biocomposite. The electrochemically-assisted deposition also allows the express modification of gold screen-printed electrodes with silica-choline oxidase biocomposite making possible the quick fabrication of cheap choline biosensors with high analytical character...
Sensors and Actuators B: Chemical, 2005
Smart (Nano) materials with biosensing functions posses enormous potential in the development of new generation stable biosensors, chemical sensors, and actuators. Recently, there is a considerable interest in using TiO 2 nanostructured materials as a film-forming material since they have high surface area, optical transparency, high bio-compatibility, and relatively good conductivity. In this work, TiO 2 oxides were used as nanoporous electrodes to study the electron transfer mechanisms of H 2 O 2 , and many interesting biological molecules, as 3,4-dihydroxyphenylacetic acid (DOPAC), ascorbic acid, guanine, l-tyrosine, acetaminophen, and -NADH, in order to assemble a new generation of chemical sensors and biosensors. A kinetic study was also reported in this paper, which demonstrated high performances towards electrocatalytic processes, obtained at nanostructured TiO 2 -modified electrodes.
Colloid and Polymer Science, 2018
Multi-walled carbon nanotubes (MWCNTs) were incorporated into the active layer of mesoporous TiO 2 films resulting in MWCNTs-TiO 2 nanocomposites with improved electrical conductivity. These MWCNTs-TiO 2 nanocomposite films were prepared by a direct mixing method and the Bdoctor blade^technique. The films were sintered at various annealing temperatures (300, 350, 400, and 450°C) in order to examine the effect of annealing temperature to the morphology and electrochemical activity of the films. The presence of anatase TiO 2 and MWCNTs has been confirmed by X-ray diffraction (XRD), field emission scanning electron microscopy (SEM), transmission electron microscopy (TEM), and Raman spectroscopy, while conductivity and electrochemical properties of the nanocomposite MWCNΤs-TiO 2 films were examined via cyclic voltammetry (CV) and spectroelectrochemistry. After successful protein immobilization (Cyt-c), the electrochemical and spectroelectrochemical behavior of these hybrid electrodes (Cyt-c/MWCNTs-TiO 2) was examined in detail and particularly the effect of MWCNTs on the interfacial electron transfer between the film electrode and the adsorbed protein molecules.
Langmuir, 2003
Positively charged proteins are electrostatically adsorbed on ultrathin metal oxide gel layers that are prepared by the surface sol-gel process. This feature was applied to assembly of multilayer films of cytochrome c (Cyt.c) and zirconium oxide. Regular growth of the alternate multilayer was verified by UV-vis absorption spectroscopy and quartz crystal microbalance measurements. The ZrO2-gel layer was uniformly covered by the Cyt.c at pH 10.0 with a thickness of 2.4 nm for the protein layer. An excess amount of Cyt.c was adsorbed at pH 7.0 to produce globular aggregates on the ZrO2-gel layer, as confirmed by scanning electron microscopy. Cyt.c showed weak adsorption at pH 4.0, since the ZrO2-gel layer had only a slight negative charge. When the ZrO2-gel layer was modified with octadecyltriethoxysilane, irreversible deposition of denatured Cyt.c was observed. In contrast, the ZrO2-gel covered by an ultrathin poly(vinyl alcohol) layer adsorbed Cyt.c without denaturation. Such Cyt.c molecules were readily desorbed by changing pH to above the isoelectric point. The surface sol-gel process provides a convenient method to immobilize water-soluble proteins through moderate electrostatic attraction.
Immobilization of cytochrome c on cysteamine-modified gold electrodes with EDC as coupling agent
Talanta, 2008
Cyclic voltammetry has been applied for the characterization of cross-linked horse heart cytochrome c (HHC) on cysteamine-modified gold electrodes. The cross-linking, i.e. amide bond formation, between the proteins was achieved by using 1-ethyl-3-(3-dimethylaminopropyl)-carbodiimide (EDC) as coupling reagent. The optimal conditions for the formation of the HHC film were determined by varying the HHC concentration. In addition the reproducibility, stability and the influence of the scan rate upon these films were investigated with cyclic voltammetry. The protein film stability in a 4-(2-hydroxyethyl)-1piperazineethanesulfonic acid (HEPES) buffer solution was tested by UV/vis absorption spectroscopy.