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Sökning: swepub > Malmö högskola > Engelska > Shleev Sergey

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1.
  • Andoralov, Viktor, et al. (författare)
  • Biofuel cell based on microscale nanostructured electrodes with inductive coupling to rat brain neurons.
  • 2013
  • Ingår i: Scientific reports. - NATURE PUBLISHING GROUP. - 2045-2322. ; 3:Nov 20, s. 3270
  • Tidskriftsartikel (refereegranskat)abstract
    • Miniature, self-contained biodevices powered by biofuel cells may enable a new generation of implantable, wireless, minimally invasive neural interfaces for neurophysiological in vivo studies and for clinical applications. Here we report on the fabrication of a direct electron transfer based glucose/oxygen enzymatic fuel cell (EFC) from genuinely three-dimensional (3D) nanostructured microscale gold electrodes, modified with suitable biocatalysts. We show that the process underlying the simple fabrication method of 3D nanostructured electrodes is based on an electrochemically driven transformation of physically deposited gold nanoparticles. We experimentally demonstrate that mediator-, cofactor-, and membrane-less EFCs do operate in cerebrospinal fluid and in the brain of a rat, producing amounts of electrical power sufficient to drive a self-contained biodevice, viz. 7 μW cm(-2) in vitro and 2 μW cm(-2) in vivo at an operating voltage of 0.4 V. Last but not least, we also demonstrate an inductive coupling between 3D nanobioelectrodes and living neurons.
2.
  • Ruzgas, Tautgirdas, et al. (författare)
  • Electrochemical characterization and application of azurin-modified gold electrodes for detection of superoxide
  • 2006
  • Ingår i: Biosensors & bioelectronics. - 0956-5663. ; 22:2, s. 213-219
  • Tidskriftsartikel (refereegranskat)abstract
    • A novel biosensor for superoxide radical (O2{radical dot}-) detection based on Pseudomonas aeruginosa azurin immobilized on gold electrode was designed. The rate constant of azurin reduction by O2{radical dot}- was found to be 105 M-1 s-1 in solution and five times lower, i.e., 0.2 × 105 M-1 s-1, for azurin coupled to gold by 3,3′-dithiobis(sulfosuccinimidylpropionate) (DTSSP). The electron transfer rate between the protein and the electrode ranged from 2 to 6 s-1. The sensitivity of this biosensor to O2{radical dot}- was 6.8 × 102 A m-2 M-1. The response to the interference substances, such as uric acid, H2O2, and dimethylsulfoxide was negligible below 10 μM. The electrode was applied in three O2{radical dot}- generating systems: (i) xanthine oxidase (XOD), (ii) potassium superoxide (KO2), and (iii) stimulated neutrophil granulocytes. The latter was compared with luminol-amplified chemiluminescence. The biosensor responded to O2{radical dot}- in all three environments, and the signals were antagonized by superoxide dismutase. © 2006 Elsevier B.V. All rights reserved.
3.
  • Shleev, Sergey, et al. (författare)
  • Simultaneous use of electrochemistry and chemiluminescence to detect reactive oxygen species produced by human neutrophils
  • 2008
  • Ingår i: Cell Biology International. - 1065-6995. ; 32:12, s. 1486-1496
  • Tidskriftsartikel (refereegranskat)abstract
    • A novel approach for the simultaneous optical and electrochemical detection of biologically produced reactive oxygen species has been developed and applied. The set-up consists of a luminol-dependent chemiluminescence assay combined with two amperometric biosensors sensitive to superoxide anion radicals (O-2(center dot-))and hydrogen peroxide (H2O2), respectively. The method permits direct, real-time in vitro determination of both extra-and intracellular O-2(center dot-) and H2O2 produced by human neutrophil granulocytes. The rate of O-2(center dot-) production by stimulated neutrophils was calculated to about 10(-17) mol s(-1) per single cell. With inhibited NADPH oxidase, a distinct extracellular release of H2O2 instead of O-2(center dot-) was obtained from stimulated neutrophils with the rate of about 3 . 10(-18) mol s(-1) per single cell. When the H2O2 release was discontinued, fast H2O2 utilisation was observed. Direct interaction with and possibly attachment of neutrophils to redox protein-modified gold electrodes, resulted in a spontaneous respiratory burst in the population of cells closely associated to the electrode surface. Hence, further stimulation of human neutrophils with a potent receptor agonist (fMLF) did not significantly increase the O-2(center dot-) sensitive amperometric response. By contrast, the H2O2 sensitive biosensor, based on an HRP-modified graphite electrode, was able to reflect the bulk concentration of H2O2, produced by stimulated neutrophils and would be very useful in modestly equipped biomedical research laboratories. In summary, the system would also be appropriate for assessment of several other metabolites in different cell types, and tissues of varying complexity, with only minor electrode modifications.
4.
  • Coman, Vasile, et al. (författare)
  • A Direct Electron Transfer-Based Glucose/Oxygen Biofuel Cell Operating in Human Serum
  • 2010
  • Ingår i: Fuel Cells. - Wiley-V C H Verlag Gmbh. - 1615-6846. ; 10:1, s. 9-16
  • Tidskriftsartikel (refereegranskat)abstract
    • We report on the fabrication and characterisation of the very first direct electron transfer-based glucose/oxygen biofuel cell (BFC) operating in neutral glucose-containing buffer and human serum. Corynascus thermophilus cellobiose dehydrogenase and Myrothecium verrucaria bilirubin oxidase were used as anodic and cathodic bioelements, respectively. The following characteristics of the mediator-, separator- and membrane-less, a priori, non-toxic and simple miniature BFC, was obtained: an open-circuit voltage of 0.62 and 0.58 V, a maximum power density of ca. 3 and 4 mu W cm(-2) at 0.37 and 0.19 V of cell voltage, in phosphate buffer and human serum, respectively.
5.
  • Coman, Vasile, et al. (författare)
  • A membrane-, mediator-, cofactor-less glucose/oxygen biofuel cell.
  • 2008
  • Ingår i: Physical chemistry chemical physics : PCCP. - Royal Society of Chemistry. - 1463-9076. ; 10:40, s. 6093-6096
  • Tidskriftsartikel (refereegranskat)abstract
    • We report the fabrication and characterisation of a non-compartmentalised, mediator and cofactor free glucose-oxygen biofuel cell based on adsorbed enzymes exhibiting direct bioelectrocatalysis, viz. cellobiose dehydrogenase from Dichomera saubinetii and laccase from Trametes hirsuta as the anodic and cathodic bioelements, respectively, with the following characteristics: an open-circuit voltage of 0.73 V; a maximum power density of 5 muW cm(-2) at 0.5 V of the cell voltage and an estimated half-life of >38 h in air-saturated 0.1 M citrate-phosphate buffer, pH 4.5 containing 5 mM glucose.
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6.
  • Falk, Magnus, et al. (författare)
  • Biofuel cell as a power source for electronic contact lenses.
  • 2012
  • Ingår i: Biosensors & bioelectronics. - Elsevier. - 1873-4235. ; 37:1, s. 38-45
  • Tidskriftsartikel (refereegranskat)abstract
    • Here we present unequivocal experimental proof that microscale cofactor- and membrane-less, direct electron transfer based enzymatic fuel cells do produce significant amounts of electrical energy in human lachrymal liquid (tears). 100μm diameter gold wires, covered with 17nm gold nanoparticles, were used to fashion three-dimensional nanostructured microelectrodes, which were biomodified with Corynascus thermophilus cellobiose dehydrogenase and Myrothecium verrucaria bilirubin oxidase as anodic and cathodic bioelements, respectively. The following characteristics of miniature glucose/oxygen biodevices operating in human tears were registered: 0.57V open-circuit voltage, about 1μWcm(-2) maximum power density at a cell voltage of 0.5V, and more than 20h operational half-life. Theoretical calculations regarding the maximum recoverable electrical energy can be extracted from the biofuel and the biooxidant, glucose and molecular oxygen, each readily available in human lachrymal liquid, fully support our belief that biofuel cells can be used as electrical power sources for so called smart contact lenses.
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7.
  • Haberska, Karolina, et al. (författare)
  • Activity of lactoperoxidase when adsorbed on protein layers
  • 2008
  • Ingår i: Talanta. - Elsevier. - 0039-9140. ; 76:5, s. 1159-1164
  • Tidskriftsartikel (refereegranskat)abstract
    • Lactoperoxidase (LPO) is an enzyme, which is used as an antimicrobial agent in a number of applications, e.g., food technology. In the majority of applications LPO is added to a homogeneous product phase or immobilised on product surface. In the latter case, however, the measurements of LPO activity are seldom reported. In this paperwe have assessed LPO enzymatic activity on bare and protein modified gold surfaces by means of electrochemistry. It was found that LPO rapidly adsorbs to bare gold surfaces resulting in an amount of LPO adsorbed of 2.9mg/m2. A lower amount of adsorbed LPO is obtained if the gold surface is exposed to bovine serum albumin, bovine or human mucin prior to LPO adsorption. The enzymatic activity of the adsorbed enzyme is in general preserved at the experimental conditions and varies only moderately when comparing bare gold and gold surface pretreated with the selected proteins. The measurement of LPO specific activity, however, indicate that it is about 1.5 times higher if LPO is adsorbed on gold surfaces containing a small amount of preadsorbed mucin in comparison to the LPO directly adsorbed on bare gold.
8.
  • Hu, LiHong, et al. (författare)
  • Reorganization Energy for Internal Electron Transfer in Multicopper Oxidases.
  • 2011
  • Ingår i: Journal of Physical Chemistry. B. - American Chemical Society. - 1520-5207. ; 115:Online September 28, 2011, s. 13111-13126
  • Tidskriftsartikel (refereegranskat)abstract
    • We have calculated the reorganization energy for the intramolecular electron transfer between the reduced type 1 copper site and the peroxy intermediate of the trinuclear cluster in the multicopper oxidase CueO. The calculations are performed at the combined quantum mechanics and molecular mechanics (QM/MM) level, based on molecular dynamics simulations with tailored potentials for the two copper sites. We obtain a reorganization energy of 91-133 kJ/mol, depending on the theoretical treatment. The two Cu sites contribute by 12 and 22 kJ/mol to this energy, whereas the solvent contribution is 34 kJ/mol. The rest comes from the protein, involving small contributions from many residues. We have also estimated the energy difference between the two electron-transfer states and show that the reduction of the peroxy intermediate is exergonic by 43-87 kJ/mol, depending on the theoretical method. Both the solvent and the protein contribute to this energy difference, especially charged residues close to the two Cu sites. We compare these estimates with energies obtained from QM/MM optimizations and QM calculations in a vacuum and discuss differences between the results obtained at various levels of theory.
9.
  • Khupova, Maria, et al. (författare)
  • Amperometric monitoring of redox activity in intact, permeabilised and lyophilised cells of the yeast Hansenula polymorpha
  • 2007
  • Ingår i: Electrochemistry Communications. - Elsevier Science Inc.. - 1388-2481. ; 9:7, s. 1480-1485
  • Tidskriftsartikel (refereegranskat)abstract
    • An effect of permeabilisation and lyophilisation of the yeast cells Hansenula polymorpha on their electrochemical behaviour in the presence of mediators, substrates (formaldehyde, glucose, methanol, ethanol), and cofactors (NAD(+), NADP(+), NADH, NADPH, glutathione) has been studied. Two amperometric techniques differing in the cell immobilisation methods were applied. The cells of a wild strain (356) and mutant strains (C-105 and KCA 33) of the yeast, grown in the presence of glucose or methanol, were used in the experiments. The intact cells revealed the highest reduction rates of mediators, 2,6-dichlorphenolindophenol (DCIP) and 2,4-benzoquinone (BQ) as measured by amperometry. The addition of formaldehyde significantly enhanced the response, if the cells were grown in the presence of glucose. The permeabilised cells showed the lowest current level in the presence of DCIP and BQ and no response to the addition of formaldehyde and NAD(+). However, the addition of NADH gave significant current surge. All these phenomena imply that the permeabilised cells lost cofactors and the activity of dehydrogenases producing NADH, but they remained the activity of NADH-ubiquinone oxidoreductase and of some components of the electron transport chain. The electrochemical behaviour of the lyophilised cells shows they are heterogeneous. The partial degradation of the outer membrane of the cells after their lyophilisation was electrochemically confirmed. (c) 2007 Elsevier B.V. All rights reserved.
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10.
  • Pita, M, et al. (författare)
  • Direct heterogeneous electron transfer reactions of fungal laccases at bare and thiol-modified gold electrodes
  • 2006
  • Ingår i: Electrochemistry Communications. - Elsevier Science Inc.. - 1388-2481. ; 8:5, s. 747-753
  • Tidskriftsartikel (refereegranskat)abstract
    • Mediatorless (direct) electron transfer between bare and thiol-modified gold electrodes and fungal laccases from different sources has been demonstrated. The electrochemical activity of the enzymes from basidiomycetes Trametes hirstita. Trametes ochracea, and Cerrena maxima under aerobic and anaerobic conditions can clearly be observed using cyclic voltammetry and spectroelectrochemistry. Bioelectroreduction of oxygen by T. hirsuta laccase immobilized on amino-thiophenol-modified gold electrodes., starting at +625 mV vs. NHE, is demonstrated and differences in bioelectrocatalysis of the enzyme immobilized on bare and thiol-modified electrodes are shown. It was found that hydrogen peroxide was one of the products of oxygen electroreduction on gold electrodes modified with fungal laccases, whereas no significant peroxide formation was observed for T. hirsuta laccase immobilised on thiol-modified gold electrodes. Thus, a hypothesis about two different mechanisms of oxygen electroreduction by fungal laccases adsorbed on bare and thiol-modified electrodes is proposed. (c) 2006 Elsevier B.V. All rights reserved.
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