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BETA
Sekretareva, Alina
Alternative names
Publications (10 of 12) Show all publications
Sekretaryova, A., Eriksson, M. & Turner, A. (2016). Bioelectrocatalytic systems for health applications. Biotechnology Advances, 34(3), 177-197
Open this publication in new window or tab >>Bioelectrocatalytic systems for health applications
2016 (English)In: Biotechnology Advances, ISSN 0734-9750, E-ISSN 1873-1899, Vol. 34, no 3, p. 177-197Article, review/survey (Refereed) Published
Abstract [en]

We present a brief overview of bioelectrocatalytic devices for in vitro health applications, including food safety and environmental analysis, focusing on microelectrode- and microfluidic-based biosensors, paper-based point-of-care devices and wearable biosensors. The main hurdles and future perspectives are discussed. We then consider the role of electron transfer between a biocatalyst and an electrode in biosensor design. Brief descriptions of indirect, direct and mediated mechanisms are given. The principal strategies, as well as recent developments for modulation of electron transfer in biocatalytic systems are summarised. In conclusion, we highlight some of the challenges associated with improving these redox systems.

Place, publisher, year, edition, pages
Elsevier, 2016
Keywords
Direct electron transfer; Mediated electron transfer; Immobilisation; Microbiosensor; Nanobiosensor; Paper-based biosensor; Wearable biosensor; Self-powered biosensor
National Category
Bioinformatics and Systems Biology
Identifiers
urn:nbn:se:liu:diva-123688 (URN)10.1016/j.biotechadv.2015.12.005 (DOI)000375500700004 ()26724183 (PubMedID)
Available from: 2016-01-08 Created: 2016-01-08 Last updated: 2017-12-01Bibliographically approved
Sekretaryova, A. N., Vagin, M. Y., Turner, A. P. .. & Eriksson, M. (2016). Electrocatalytic Currents from Single Enzyme Molecules. Journal of the American Chemical Society, 138(8), 2504-2507
Open this publication in new window or tab >>Electrocatalytic Currents from Single Enzyme Molecules
2016 (English)In: Journal of the American Chemical Society, ISSN 0002-7863, E-ISSN 1520-5126, Vol. 138, no 8, p. 2504-2507Article in journal (Refereed) Published
Abstract [en]

Single molecule enzymology provides an opportunity to examine details of enzyme mechanisms that are not distinguishable in biomolecule ensemble studies. Here we report, for the first time, detection of the current produced in an electrocatalytic reaction by a single redox enzyme molecule when it collides with an ultramicroelectrode. The catalytic process provides amplification of the current from electron-transfer events at the catalyst leading to a measurable current. This new methodology monitors turnover of a single enzyme molecule. The methodology might complement existing single molecule techniques, giving further insights into enzymatic mechanisms and filling the gap between fundamental understanding of biocatalytic processes and their potential for bioenergy production.

Place, publisher, year, edition, pages
American Chemical Society (ACS), 2016
National Category
Chemical Sciences Chemical Engineering Chemical Process Engineering
Identifiers
urn:nbn:se:liu:diva-125241 (URN)10.1021/Jacs.5b13149 (DOI)000371453700011 ()
Note

Funding agencies:  Swedish research council Formas [245-2010-1062]; research center Security Link (VINNOVA ) [2009-00966]; Centre in Nano Science and Technology (CeNano, Linkoping University)

Vid tiden för dispuation förelåg publikationen endast som manuskript

Available from: 2016-02-17 Created: 2016-02-17 Last updated: 2017-11-30Bibliographically approved
Sekretaryova, A. (2016). Facilitating electron transfer in bioelectrocatalytic systems. (Doctoral dissertation). Linköping: Linköping University Electronic Press
Open this publication in new window or tab >>Facilitating electron transfer in bioelectrocatalytic systems
2016 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

Bioelectrocatalytic systems are based on biological entities, such as enzymes, whole cells, parts of cells or tissues, which catalyse electrochemical processes that involve the interaction between chemical change and electrical energy. In all cases, biocatalysis is implemented by enzymes, isolated or residing inside cells or part of cells. Electron transfer (ET) phenomena, within the protein molecules and between biological redox systems and electronics, enable the development of various bioelectrocatalytic systems, which can be used both for fundamental investigations of enzymatic biological processes by electrochemical methods and for applied purposes, such as power generation, bioremediation, chemical synthesis and biosensing.

Electrical communication between the biocatalyst’s redox centre and an electrode is essential for the functioning of the system. This can be established using two main mechanisms: indirect ET and direct ET. The efficiency of the ET influences important parameters such as the turnover rate of the biocatalyst, the generated current density and partially the stability of the system, which in their turn determine response time, sensitivity, detection limit and operational stability of biosensing devices or the power densities and current output of biofuel cells, and hence should be carefully considered when designing bioelectrocatalytic systems.

This thesis focuses on approaches that facilitate ET in bioelectrocatalytic systems based on indirect and direct ET mechanisms. Both fundamental aspects of ET in bioelectrocatalytic systems and applications of such systems for biosensing and power generation are considered. First, a new hydrophobic mediator for oxidases – unsubstituted phenothiazine and its improved ET properties in comparison with commonly used mediators are discussed. Application of the mediator in electrochemical biosensors is demonstrated by glucose, lactate and cholesterol sensing. Utilisation of mediated biocatalytic cholesterol oxidation, as the anodic reaction for the construction of a biofuel cell acting as a power supply and an analytical device at the same time, is investigated to deliver a selfpowered biosensor. Also the enhancement of mediated bioelectrocatalysis by employment of microelectrodes as a transducer is examined. The effect of surface roughness on the current response of the microelectrodes under conditions of convergent diffusion is considered. The applicability of the laccase-based system for total phenol analysis of weakly supported water is demonstrated. Finally, a new electrochemical approach derived from collision-based electrochemistry applicable for examination of the ET process of a single enzyme molecule is described.

All together, the results presented in this thesis contribute to the solution of the ‘electronic coupling problem’, arising when interfacing biomolecules with electronics and limiting the performance of bioelectrocatalytic systems in specific applications. The developed methods to facilitate ET will hopefully promote future biosensing devices and biofuel cells. I believe the new approach for investigation of ET processes at a single enzyme molecule will complement existing single molecule techniques, giving further insights into enzymatic ET mechanisms at the molecular level and filling the gap between fundamental understanding of biocatalytic processes and their potential for bioenergy production.

Place, publisher, year, edition, pages
Linköping: Linköping University Electronic Press, 2016. p. 74
Series
Linköping Studies in Science and Technology. Dissertations, ISSN 0345-7524 ; 1738
National Category
Chemical Sciences Chemical Engineering Chemical Process Engineering
Identifiers
urn:nbn:se:liu:diva-125242 (URN)10.3384/diss.diva-125242 (DOI)978-91-7685-841-7 (ISBN)
Public defence
2016-03-18, Planck, Fysikhuset, Campus Valla, Linköping, 10:15 (English)
Opponent
Supervisors
Available from: 2016-02-17 Created: 2016-02-17 Last updated: 2017-11-03Bibliographically approved
Sekretaryova, A., Volkov, A. V., Zozoulenko, I. V., Turner, A., Vagin, M. Y. & Eriksson, M. (2016). Total phenol analysis of weakly supported water using a laccase-based microband biosensor.. Analytica Chimica Acta, 907, 45-53
Open this publication in new window or tab >>Total phenol analysis of weakly supported water using a laccase-based microband biosensor.
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2016 (English)In: Analytica Chimica Acta, ISSN 0003-2670, E-ISSN 1873-4324, Vol. 907, p. 45-53Article in journal (Refereed) Published
Abstract [en]

The monitoring of phenolic compounds in wastewaters in a simple manner is of great importance for environmental control. Here, a novel screen printed laccase-based microband array for in situ, total phenol estimation in wastewaters and for water quality monitoring without additional sample pre-treatment is presented. Numerical simulations using the finite element method were utilized for the characterization of micro-scale graphite electrodes. Anodization followed by covalent modification was used for the electrode functionalization with laccase. The functionalization efficiency and the electrochemical performance in direct and catechol-mediated oxygen reduction were studied at the microband laccase electrodes and compared with macro-scale electrode structures. The reduction of the dimensions of the enzyme biosensor, when used under optimized conditions, led to a significant improvement in its analytical characteristics. The elaborated microsensor showed fast responses towards catechol additions to tap water – a weakly supported medium – characterized by a linear range from 0.2 to 10 μM, a sensitivity of 1.35 ± 0.4 A M−1 cm−2 and a dynamic range up to 43 μM. This enhanced laccase-based microsensor was used for water quality monitoring and its performance for total phenol analysis of wastewater samples from different stages of the cleaning process was compared to a standard method.

Place, publisher, year, edition, pages
Elsevier, 2016
Keywords
Laccase; microelectrode; microband; electrochemical modeling; total phenol analysis; wastewater
National Category
Analytical Chemistry
Identifiers
urn:nbn:se:liu:diva-123677 (URN)10.1016/j.aca.2015.12.006 (DOI)000368422900005 ()
Note

Funding agencies: Swedish research council Formas [245-2010-1062]; research centre Security Link [VINNOVA 2009-00966]; Norrkopings fond for Forskning och Utveckling; VINNOVA

Available from: 2016-01-07 Created: 2016-01-07 Last updated: 2017-12-01Bibliographically approved
Vagin, M. Y., Sekretareva, A., Lindgren, P., Håkansson, A., Eriksson, M., Lundström, I., . . . Yakimova, R. (2015). Direct bioelectrocatalysis on anodized epitaxial graphene. In: Program of the XXIII International Symposium on Bioelectrochemistry and Bioenergetics of the Bioelectrochemical Society14-18 June, 2015Malmö, Sweden: . Paper presented at Program of the XXIII International Symposium on Bioelectrochemistry and Bioenergetics of the Bioelectrochemical Society 14-18 June, 2015 Malmö, Sweden (pp. 170-170). Lausanne: Bioelectrochemical Society
Open this publication in new window or tab >>Direct bioelectrocatalysis on anodized epitaxial graphene
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2015 (English)In: Program of the XXIII International Symposium on Bioelectrochemistry and Bioenergetics of the Bioelectrochemical Society14-18 June, 2015Malmö, Sweden, Lausanne: Bioelectrochemical Society , 2015, p. 170-170Conference paper, Published paper (Other academic)
Abstract [en]

Graphene as a nanomaterial consisting of a single layer sheets of atoms of carbon in hexagonal arrangement is making a significant impact in variety of technologies such as energy storage and chemical analysis. The significant attention paid to this thinnest nanomaterial resulted in thousands of patent applications is due to its staggering properties. Due to the planar conjugation of the sp2bonds in graphene, two-dimensional electrical conduction is highly efficient. On the contrary, the efficiency of electron exchange at the out-of-plane of the graphene sheet is small. The significant difference of the densities of electronic states at in-plane and out-of-plane of graphene sheet determines two distinct structural contributions (basal and edge plane respectively) to the behavior of all graphitic materials yielding the chemical and electrochemical anisotropy. Being the simplest building block of graphitic materials, graphene offers the possibility to study the behavior on the simplest level of structural organization. However, the major effort of the recent electrochemical studies of graphene were done using a bulk materials based on graphene flakes possessing the domination of edges of high reactivity. The planar orientation of graphene sheets with controllable exposure of basal plane is achievable via the growth by chemical vapor deposition or by epitaxial flash annealing on crystalline structures of silicon carbide. The slow growth of graphene onto crystalline support during annealing in the inert atmosphere results in a development of a high quality graphene monolayer attached to the solid insulating support. The creation of sp3-type reactive defects on the basal plane of graphite can be achieved by anodization at high anodic potentials.

We developed the procedure for the real-time monitoring of epitaxial graphene anodization. The changes of electrochemical properties of graphene monolayer with anodization have been comparatively investigated by electrochemical methods. The estimation of specific capacitance in pure electrolyte and in conditions of Faradaic process has been carried out. Finally, the direct electrocatalysis of laccase (Trametes versicolor) has been used as an electrode reaction to probe the reactivities of anodized epitaxial graphene and conventional carbon materials.

Place, publisher, year, edition, pages
Lausanne: Bioelectrochemical Society, 2015
National Category
Condensed Matter Physics
Identifiers
urn:nbn:se:liu:diva-122686 (URN)
Conference
Program of the XXIII International Symposium on Bioelectrochemistry and Bioenergetics of the Bioelectrochemical Society 14-18 June, 2015 Malmö, Sweden
Available from: 2015-11-16 Created: 2015-11-16 Last updated: 2017-11-03Bibliographically approved
Sekretareva, A., Vagin, M., Volkov, A. V., Zozoulenko, I. V., Turner, A. & Eriksson, M. (2015). Screen printed microband array based biosensor for water monitoring. In: The Frumkin Symposium: . Paper presented at The Frumkin Symposium, 21-23 October 2015, Moscow, Russia.
Open this publication in new window or tab >>Screen printed microband array based biosensor for water monitoring
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2015 (English)In: The Frumkin Symposium, 2015Conference paper, Oral presentation with published abstract (Refereed)
National Category
Biological Sciences
Identifiers
urn:nbn:se:liu:diva-123698 (URN)
Conference
The Frumkin Symposium, 21-23 October 2015, Moscow, Russia
Available from: 2016-01-08 Created: 2016-01-08 Last updated: 2017-11-03
Sekretareva, A., Vagin, M. Y., Volkov, A. V., Zozoulenko, I. V., Turner, A. P. .. & Eriksson, M. (2015). Total phenol analysis of water using a laccase-based microsensor array. In: Program of the XXIII International Symposium on Bioelectrochemistry and Bioenergetics of the Bioelectrochemical Society. 14-18 June, 2015. Malmö, Sweden: . Paper presented at The XXIII International Symposium on Bioelectrochemistry and Bioenergetics of the Bioelectrochemical Society. 14-18 June, 2015. Malmö, Sweden (pp. 155-155). Lausanne: Bioelectrochemical Society
Open this publication in new window or tab >>Total phenol analysis of water using a laccase-based microsensor array
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2015 (English)In: Program of the XXIII International Symposium on Bioelectrochemistry and Bioenergetics of the Bioelectrochemical Society. 14-18 June, 2015. Malmö, Sweden, Lausanne: Bioelectrochemical Society , 2015, p. 155-155Conference paper, Published paper (Other academic)
Abstract [en]

The monitoring of phenolic compounds in raw waters and wastewaters is of great importance for environmental control. Use of biosensors for rapid, specific and simple detection of phenolic compounds is a promising approach. A number of biosensors have been developed for phenol detection. A general drawback of previously reported biosensors is their insufficient detection limits for phenols in water samples. One way to improve the detection limit is by the use of microelectrodes.

Microband design of the microelectrodes combines convergent mass transport due to the microscale width and high output currents due to the macroscopic length. Among the various techniques available for microband electrode fabrication, we have chosen screen-printing which is a cost-effective production method.

In this study, we report on the development of a laccase-based microscale biosensor operating under a convergent diffusion regime. Screen-printing followed by simple cutting was utilized for the fabrication of graphite microbands as a platform for further covalent immobilization of laccase. Numerical simulations, utilizing the finite element method with periodic boundary conditions, were used for modeling the voltammetric response of the developed microband electrodes. Anodization followed by covalent immobilization was used for the electrode modification with laccase. Direct and mediated laccase bioelectrocatalytic oxidation of phenols was studied on macro- and microscale graphite electrodes. Significant enhancement of the analytical performance was achieved by the establishment of convergent diffusion in the microscale sensor. Finally, the developed microsensor was utilized to monitor phenolic compounds in real waste water.

Place, publisher, year, edition, pages
Lausanne: Bioelectrochemical Society, 2015
National Category
Biochemistry and Molecular Biology
Identifiers
urn:nbn:se:liu:diva-122687 (URN)
Conference
The XXIII International Symposium on Bioelectrochemistry and Bioenergetics of the Bioelectrochemical Society. 14-18 June, 2015. Malmö, Sweden
Available from: 2015-11-16 Created: 2015-11-16 Last updated: 2017-11-03Bibliographically approved
Vagin, M., Sekretareva, A., Sanchez, R., Lundström, I., Winquist, F. & Eriksson, M. (2014). Arrays of Screen-Printed Graphite Microband Electrodes as a Versatile Electroanalysis Platform. ChemElectroChem, 1(4), 755-762
Open this publication in new window or tab >>Arrays of Screen-Printed Graphite Microband Electrodes as a Versatile Electroanalysis Platform
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2014 (English)In: ChemElectroChem, ISSN 2196-0216, Vol. 1, no 4, p. 755-762Article in journal (Refereed) Published
Abstract [en]

Arrays of microband electrodes were developed by screen printing followed by cutting, which enabled the realization of microband arrays at the cut edge. The microband arrays of different designs were characterized by physical and electro-chemical methods. In both cases, the methods showed that the microband width was around 5 mm. Semi-steady-state cyclic voltammetry responses were observed for redox probes, and chronocoulometric measurements showed the establishment of convergent diffusion regimes characterized by current densities similar to those of a single microelectrode. The analytical performance of the electrode system and its versatility were illustrated with two electrochemical assays: detection of ascorbic acid through direct oxidation and a mediated glucose biosensor fabricated by dip coating. Due to convergent mass transport, both systems showed an enhancement in their analytical characteristics. The developed approach can be adapted to automated electrode recovery.

Place, publisher, year, edition, pages
Wiley, 2014
Keywords
graphite screen printing; microarrays; microband; sensors; voltammetry
National Category
Physical Sciences Chemical Sciences
Identifiers
urn:nbn:se:liu:diva-109289 (URN)10.1002/celc.201300204 (DOI)000338296100010 ()
Available from: 2014-08-11 Created: 2014-08-11 Last updated: 2017-11-03Bibliographically approved
Sekretaryova, A., Beni, V., Eriksson, M., Karyakin, A. A., Turner, A. & Vagin, M. (2014). Cholesterol Self-Powered Biosensor. Analytical Chemistry, 86(19), 9540-9547
Open this publication in new window or tab >>Cholesterol Self-Powered Biosensor
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2014 (English)In: Analytical Chemistry, ISSN 0003-2700, E-ISSN 1520-6882, Vol. 86, no 19, p. 9540-9547Article in journal (Refereed) Published
Abstract [en]

Monitoring the cholesterol level is of great importance, especially for people with high risk of developing heart disease. Here we report on reagentless cholesterol detection in human plasma with a novel single-enzyme, membrane-free, self-powered biosensor, in which both cathodic and anodic bioelectrocatalytic reactions are powered by the same substrate. Cholesterol oxidase was immobilized in a sol-gel matrix on both the cathode and the anode. Hydrogen peroxide, a product of the enzymatic conversion of cholesterol, was electrocatalytically reduced, by the use of Prussian blue, at the cathode. In parallel, cholesterol oxidation catalyzed by mediated cholesterol oxidase occurred at the anode. The analytical performance was assessed for both electrode systems separately. The combination of the two electrodes, formed on high surface-area carbon cloth electrodes, resulted in a self-powered biosensor with enhanced sensitivity (26.0 mA M-1 cm(-2)), compared to either of the two individual electrodes, and a dynamic range up to 4.1 mM cholesterol. Reagentless cholesterol detection with both electrochemical systems and with the self-powered biosensor was performed and the results were compared with the standard method of colorimetric cholesterol quantification.

Place, publisher, year, edition, pages
American Chemical Society, 2014
National Category
Physical Sciences Biological Sciences
Identifiers
urn:nbn:se:liu:diva-112176 (URN)10.1021/ac501699p (DOI)000343017100031 ()25164485 (PubMedID)
Note

Funding Agencies|Swedish research council Formas; research centre Security Link; Swedish Institute

Available from: 2014-11-18 Created: 2014-11-18 Last updated: 2017-12-05
Sekretaryova, A. (2014). Novel reagentless electrodes for biosensing. (Licentiate dissertation). Linköping: Linköping University Electronic Press
Open this publication in new window or tab >>Novel reagentless electrodes for biosensing
2014 (English)Licentiate thesis, comprehensive summary (Other academic)
Abstract [en]

Analytical chemical information is needed in all areas of human activity including health care, pharmacology, food control and environmental chemistry. Today one of the main challenges in analytical chemistry is the development of methods to perform accurate and sensitive rapid analysis and monitoring of analytes in ‘real’ samples. Electrochemical biosensors are ideally suited for these applications.

Despite the wide application of electrochemical biosensors, they have some limitations. Thus, there is a demand on improvement of biosensor performance together with a necessity of simplification required for their mass production. In this thesis the work is focused on the development of electrochemical sensors with improved performance applicable for mass production, e.g. by screen printing.

Biosensors using immobilized oxidases as the bio-recognition element are among the most widely used electrochemical devices. Electrical communication between redox enzymes and electrodes can be established by using natural or synthetic electron carriers as mediators. However, sensors based on soluble electronshuttling redox couples have low operational stability due to the leakage of water-soluble mediators to the solution. We have found a new hydrophobic mediator for oxidases – unsubstituted phenothiazine. Phenothiazine and glucose oxidase, lactate oxidase or cholesterol oxidase were successfully co-immobilized in a sol-gel membrane on a screen-printed electrode to construct glucose, lactate and cholesterol biosensors, respectively. All elaborated biosensors with phenothiazine as a mediator exhibited long-term operational stability. A kinetic study of the mediator has shown that phenothiazine is able to function as an efficient mediator in oxidase-based biosensors.

To improve sensitivity of the biosensors and simplify their production we have developed a simple approach for production of graphite microelectrode arrays. Arrays of microband electrodes were produced by screen printing followed by scissor cutting, which enabled the realization of microband arrays at the cut edge. The analytical performance of the system is illustrated by the detection of ascorbic acid through direct oxidation and by detection of glucose using a phenothiazine mediated glucose biosensor. Both systems showed enhanced sensitivity due to improved mass transport. Moreover, the developed approach can be adapted to automated electrode recovery.

Finally, two enzyme-based electrocatalytic systems with oxidation and reduction responses, respectively, have been combined into a fuel cell generating a current as an analytical output (a so-called self-powered biosensor). This was possible as a result of the development of the phenothiazine mediated enzyme electrodes, which enabled the  construction of a cholesterol biosensor with self-powered configuration. The biosensor generates a current when analyte (cholesterol) is added to the cell. The biosensor has been applied for whole plasma analysis.

All developed concepts in the thesis are compatible with a wide range of applications and some of them may even be possible to realize in a fully integrated biosensor unit based on printed electronics.

Place, publisher, year, edition, pages
Linköping: Linköping University Electronic Press, 2014. p. 53
Series
Linköping Studies in Science and Technology. Thesis, ISSN 0280-7971 ; 1689
National Category
Analytical Chemistry
Identifiers
urn:nbn:se:liu:diva-112345 (URN)10.3384/lic.diva-112345 (DOI)978-91-7519-187-4 (ISBN)
Presentation
2014-11-28, Shrödinger, Fysikhuset, Campus Valla, Linköpings universitet, Linköping, 13:15 (English)
Opponent
Supervisors
Available from: 2014-11-24 Created: 2014-11-24 Last updated: 2017-11-03Bibliographically approved
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