TY  - JOUR
A1  - Stöcklein, Walter F. M.
A1  - Warsinke, Axel
A1  - Micheel, Burkhard
A1  - Höhne, Wolfgang
A1  - Woller, Jochen
A1  - Kempter, Gerhard
A1  - Scheller, Frieder W.
T1  - Characterization of a monoclonal antibody and its Fab fragment against diphenylurea hapten with BIA
Y1  - 1998
SN  - 3-8154-3540-4
ER  - 
TY  - JOUR
A1  - Warsinke, Axel
A1  - Stancik, L.
A1  - Macholán, L.
A1  - Pfeiffer, Dorothea
A1  - Scheller, Frieder W.
T1  - Biosensors for food analysis : application of biosensors to food requirements
Y1  - 1998
SN  - 0-85404-750-6
ER  - 
TY  - JOUR
A1  - Stöcklein, Walter F. M.
A1  - Warsinke, Axel
A1  - Micheel, Burkhard
A1  - Höhne, Wolfgang
A1  - Woller, Jochen
A1  - Kempter, Gerhard
A1  - Scheller, Frieder W.
T1  - Detection of diphenylurea derivatives with biospecific interaction analysis (BIA) : Kinetic investigations
Y1  - 1997
ER  - 
TY  - JOUR
A1  - Spricigo, Roberto
A1  - Dronov, Roman
A1  - Lisdat, Fred
A1  - Leimkühler, Silke
A1  - Scheller, Frieder W.
A1  - Wollenberger, Ursula
T1  - Electrocatalytic sulfite biosensor with human sulfite oxidase co-immobilized with cytochrome c in a polyelectrolyte-containing multilayer
N2  - An efficient electrocatalytic biosensor for sulfite detection was developed by co-immobilizing sulfite oxidase and cytochrome c with polyaniline sulfonic acid in a layer-by-layer assembly. QCM, UV-Vis spectroscopy and cyclic voltammetry revealed increasing loading of electrochemically active protein with the formation of multilayers. The sensor operates reagentless at low working potential. A catalytic oxidation current was detected in the presence of sulfite at the modified gold electrode, polarized at +0.1 V ( vs. Ag/AgCl 1 M KCl). The stability of the biosensor performance was characterized and optimized. A 17-bilayer electrode has a linear range between 1 and 60 mu M sulfite with a sensitivity of 2.19 mA M-1 sulfite and a response time of 2 min. The electrode retained a stable response for 3 days with a serial reproducibility of 3.8% and lost 20% of sensitivity after 5 days of operation. It is possible to store the sensor in a dry state for more than 2 months. The multilayer electrode was used for determination of sulfite in unspiked and spiked samples of red and white wine. The recovery and the specificity of the signals were evaluated for each sample.
Y1  - 2009
UR  - http://www.springerlink.com/content/100417
U6  - https://doi.org/10.1007/s00216-008-2432-y
SN  - 1618-2642
ER  - 
TY  - JOUR
A1  - Ehrentreich-Förster, Eva
A1  - Shishniashvili, D.
A1  - Song, Min Ik
A1  - Scheller, Frieder W.
T1  - Study of antioxidative substances by means of a ssuperoxide sensor
Y1  - 1998
ER  - 
TY  - JOUR
A1  - Kulys, J.
A1  - Drungiliene, A.
A1  - Wollenberger, Ursula
A1  - Scheller, Frieder W.
T1  - Membrane covered carbon paste electrode for the electrochemical determination of perioxidase and microperoxidase in a flow system
Y1  - 1998
ER  - 
TY  - JOUR
A1  - Jin, Wen
A1  - Bernhardt, Rita
A1  - Stöcklein, Walter F. M.
A1  - Scheller, Frieder W.
T1  - Direct electron transfer of adrenodoxin-a [2Fe-2S] protein-- and its mutants on modified gold electrode
Y1  - 1998
ER  - 
TY  - JOUR
A1  - Wollenberger, Ursula
A1  - Neumann, B.
A1  - Scheller, Frieder W.
T1  - Development of a biomimetic alkane sensor f
Y1  - 1998
ER  - 
TY  - JOUR
A1  - Scheller, Frieder W.
T1  - Biosensorik
Y1  - 1998
ER  - 
TY  - JOUR
A1  - Scheller, Frieder W.
A1  - Pfeiffer, Dorothea
A1  - Lisdat, Fred
A1  - Bauer, Christian G.
A1  - Gajovic, Nenad
T1  - Enzyme biosensors based on oxygen detection
Y1  - 1998
ER  - 
TY  - JOUR
A1  - Bogdanovskaya, V. A.
A1  - Fridman, Vadim
A1  - Tarasevich, M. R.
A1  - Scheller, Frieder W.
T1  - Bioelectrocatalysis by immobilized peroxidase : the reaction mechanism and the possibility of electroanalytical detection of both inhibitors and activators of enzyme
Y1  - 1994
ER  - 
TY  - JOUR
A1  - Kirstein, Dieter
A1  - Kirstein, Lincoln
A1  - Scheller, Frieder W.
A1  - Dieckmann, St.
A1  - Ronnenberg, J.
A1  - Beckmann, Dieter
A1  - Weckenbrock, E.
T1  - Elektroenzymatische Reduktion von Nitrat
Y1  - 1994
ER  - 
TY  - JOUR
A1  - Wollenberger, Ursula
A1  - Neumann, B.
A1  - Riedel, K.
A1  - Scheller, Frieder W.
T1  - Enzyme and microbial sensors for phosphate, phenols, pesticides and peroxides
Y1  - 1994
ER  - 
TY  - JOUR
A1  - Yarman, Aysu
A1  - Scheller, Frieder W.
T1  - Coupling biocatalysis with molecular imprinting in a biomimetic sensor
JF  - Angewandte Chemie : a journal of the Gesellschaft Deutscher Chemiker ; International edition
KW  - biomimetic sensors
KW  - electropolymers
KW  - enzymes
KW  - hierarchical structures
KW  - molecularly imprinted polymers
Y1  - 2013
U6  - https://doi.org/10.1002/anie.201305368
SN  - 1433-7851
SN  - 1521-3773
VL  - 52
IS  - 44
SP  - 11521
EP  - 11525
PB  - Wiley-VCH
CY  - Weinheim
ER  - 
TY  - JOUR
A1  - Scheller, Frieder W.
A1  - Pfeiffer, Dorothea
T1  - Commercial devices based on amperometric biosensors
Y1  - 1997
ER  - 
TY  - JOUR
A1  - Schulmeister, Thomas
A1  - Rose, Jürgen
A1  - Scheller, Frieder W.
T1  - Mathematical modelling of exponential amplification in membrane-based enzyme sensors
Y1  - 1997
ER  - 
TY  - JOUR
A1  - Warsinke, Axel
A1  - Benkert, Alexander
A1  - Scheller, Frieder W.
T1  - Biomolecular modules for creatinine determination
Y1  - 1996
ER  - 
TY  - JOUR
A1  - Stöcklein, Walter F. M.
A1  - Scheller, Frieder W.
T1  - Laccase : a marker enzyme for solvent modified immunoassays
Y1  - 1996
ER  - 
TY  - JOUR
A1  - Halámek, Jan
A1  - Wollenberger, Ursula
A1  - Stöcklein, Walter F. M.
A1  - Scheller, Frieder W.
T1  - Development of a biosensor for glycated hemoglobin
N2  - The development of an electrochemical piezoelectric sensor for the detection of glycated hemoglobin is presented. The total hemoglobin (Hb) content is monitored with a mass-sensitive quartz crystal modified with surfactants, and the glycated fraction of the immobilized Hb is determined by subsequent voltarnmetric measurement of the coupled ferroceneboronic acid. Different modifications of the sensor were tested for their hemoglobin binding ability. Deoxycholate (DOCA) was found to be the most suitable among the examined modifiers. Piezoelectric quartz crystals with gold electrodes were modified with DOCA by covalent binding to a pre-formatted 4-aminothiophenol monolayer. The properties of the Hb binding to DOCA and the pH effect on this interaction were studied. In the proposed assay for glycated hemoglobin at first an Hb sample is incubated with ferroceneboronic acid (FcBA), which binds to the fructosyl residue of the glycated Hb. Then this preincubated Hb sample is allowed to interact with the DOCA-modified piezoelectric quartz crystal. The binding is monitored by quartz crystal nanobalance QCN). The amount of FcBA present on the sensor surface is determined by square wave voltammetry. The binding of FcBA results in well-defined peaks with an EO' of +200 mV versus Ag/AgC1 (1 M KC1). The peak height depends on the degree of glycated Hb in the sample ranging from 0% to 20% of total Hb. The regeneration of the sensing surface is achieved by pepsin digestion of the deposited Hb. Thus the sensor can be re-used more than 30 times.
Y1  - 2007
UR  - http://www.sciencedirect.com/science/journal/00134686
U6  - https://doi.org/10.1016/j.electacta.2007.03.059
SN  - 0013-4686
ER  - 
TY  - JOUR
A1  - Halámek, Jan
A1  - Wollenberger, Ursula
A1  - Stöcklein, Walter F. M.
A1  - Warsinke, Axel
A1  - Scheller, Frieder W.
T1  - Signal amplification in immunoassays using labeling via boronic acid binding to the sugar moiety of immunoglobulin G : proof of concept for glycated hemoglobin
N2  - A novel electrochemical immunoassay based on the multiple affinity labeling of the indicator antibody with an electro-active tag is presented. The concept is illustrated for the determination of the glycated hemoglobin HbA1c in hemoglobin samples. Hemoglobin is adsorbed to the surfactant-modified surface of a piezoelectric quartz crystal. Whereas the quartz crystal nanobalance is used to validate the total Hb binding, the HbA1c on the sensor surface is recognized by an antibody and quantified electrochemically after the sugar moieties of the antibody have been labeled in-situ with ferroceneboronic acid. The sensitivity of this sensor is about threefold higher than the sensitivity of a hemoglobin sensor, where the ferroceneboronic acid is bound directly to HbA1c.
Y1  - 2007
UR  - http://www.informaworld.com/openurl?genre=journal&issn=0003-2719
U6  - https://doi.org/10.1080/00032710701327096
SN  - 0003-2719
ER  - 
TY  - JOUR
A1  - Scheller, Frieder W.
T1  - Tribute to Guenter Gauglitz (Editorial)
Y1  - 2009
UR  - http://www.springerlink.com/content/100417
U6  - https://doi.org/10.1007/s00216-008-2548-0
SN  - 1618-2642
ER  - 
TY  - JOUR
A1  - Yarman, Aysu
A1  - Wollenberger, Ursula
A1  - Scheller, Frieder W.
T1  - Sensors based on cytochrome P450 and CYP mimicking systems
JF  - ELECTROCHIMICA ACTA
N2  - Cytochrome P450 enzymes (CYPs) act on more than 90 percent of all drugs currently on the market. The catalytic cycle requires electron supply to the heme iron in the presence of oxygen. Electrochemistry allows to characterise the reaction mechanism of these redox enzymes by observing the electron transfer in real time. According to the number of publications on protein electrochemistry CYP has the third position after glucose oxidase and cytochrome c. CYP based enzyme electrodes for the quantification of drugs, metabolites or pesticides have been developed using different iso-enzymes. A crucial step in the sensor development is the efficiency of coupling the biocatalytic systems with the electrode is. In the 1970s the direct electron transfer of heme and heme peptides called microperoxidases (MPs) was used as model of oxidoreductases. They exhibit a broad substrate spectrum including hydroxylation of selected aromatic substrates, demethylation and epoxidation by means of hydrogen peroxide. It overlaps with that of P450 making heme and MPs to alternate recognition elements in biosensors for the detection of typical CYP substrates. In these enzyme electrodes the signal is generated by the conversion of all substrates thus representing in complex media an overall parameter. By combining the biocatalytic substrate conversion with selective binding to a molecularly imprinted polymer layer the specificity has been improved. Here we discuss different approaches of biosensors based on CYP, microperoxidases and catalytically active MIPs and discuss their potential as recognition elements in biosensors. The performance of these sensors and their further development are discussed. (C) 2013 Elsevier Ltd. All rights reserved.
KW  - Cytochrome P450
KW  - Microperoxidases
KW  - Catalytically active molecularly imprinted polymers
KW  - Biosensors
KW  - Personalised medicine
Y1  - 2013
U6  - https://doi.org/10.1016/j.electacta.2013.03.154
SN  - 0013-4686
SN  - 1873-3859
VL  - 110
SP  - 63
EP  - 72
PB  - PERGAMON-ELSEVIER SCIENCE LTD
CY  - OXFORD
ER  - 
TY  - JOUR
A1  - Lehmann, Claudia
A1  - Wollenberger, Ursula
A1  - Brigelius-Flohé, Regina
A1  - Scheller, Frieder W.
T1  - Bioelectrocatalysis by a selenoenzyme
Y1  - 1998
ER  - 
TY  - JOUR
A1  - Kirstein, Dieter
A1  - Kirstein, Lincoln
A1  - Scheller, Frieder W.
A1  - Borcherding, H.
T1  - Amperometric nitrate biosensors on the basis of Pseudomonas stutzeri nitrate reductase
Y1  - 1998
ER  - 
TY  - JOUR
A1  - Scheller, Frieder W.
T1  - Neue Dimensionen der Biosensorik
Y1  - 1998
ER  - 
TY  - JOUR
A1  - Jin, Wen
A1  - Wollenberger, Ursula
A1  - Scheller, Frieder W.
T1  - PQQ as redox shuttle for quinoprotein glucose dehydrogenase
Y1  - 1998
ER  - 
TY  - JOUR
A1  - Stöcklein, Walter F. M.
A1  - Warsinke, Axel
A1  - Micheel, Burkhard
A1  - Kempter, Gerhard
A1  - Höhne, Wolfgang
A1  - Scheller, Frieder W.
T1  - Diphenylurea hapten sensing with a monoclonal antibody and its Fab fragment : kinetic and thermodynamic investigations
Y1  - 1998
ER  - 
TY  - JOUR
A1  - Eremenko, Arkadi V.
A1  - Bauer, Christian G.
A1  - Makower, Alexander
A1  - Kanne, Beate
A1  - Baumgarten, Horst
A1  - Scheller, Frieder W.
T1  - The development of a non-competitive immunoenzymometric Assay (IEMA) of cocaine
Y1  - 1998
ER  - 
TY  - JOUR
A1  - Streffer, Katrin
A1  - Kaatz, Helvi
A1  - Bauer, Christian G.
A1  - Makower, Alexander
A1  - Schulmeister, Thomas
A1  - Scheller, Frieder W.
A1  - Peter, Martin G.
A1  - Wollenberger, Ursula
T1  - Application of a sensitive catechol detector for determination of tyrosinase inhibitors
Y1  - 1998
ER  - 
TY  - JOUR
A1  - Huang, T.
A1  - Warsinke, Axel
A1  - Kuwana, T.
A1  - Scheller, Frieder W.
T1  - The determination of L-phenylalanine based on a novel NADH-detecting biosensor
Y1  - 1998
ER  - 
TY  - JOUR
A1  - Bauer, Christian G.
A1  - Eremenko, A. V.
A1  - Kühn, A.
A1  - Kürzinger, K.
A1  - Markower, Alexander
A1  - Scheller, Frieder W.
T1  - Automated amplifield flow immunoassay for cocaine
Y1  - 1998
ER  - 
TY  - JOUR
A1  - Wollenberger, Ursula
A1  - Jin, Wen
A1  - Bernhardt, Rita
A1  - Lehmann, Claudia
A1  - Stöcklein, Walter F. M.
A1  - Brigelius-Flohé, Regina
A1  - Scheller, Frieder W.
T1  - Funktionalisierung von Elektroden für den direkten heterogenen Elektrotransfer
Y1  - 1998
ER  - 
TY  - JOUR
A1  - Gajovic, Nenad
A1  - Warsinke, Axel
A1  - Scheller, Frieder W.
T1  - A bienzyme electrode for L-malate based on a novel and general design
Y1  - 1998
ER  - 
TY  - JOUR
A1  - Lisdat, Fred
A1  - Ho, Wah O.
A1  - Wollenberger, Ursula
A1  - Scheller, Frieder W.
A1  - Richter, Torsten
A1  - Bilitewski, Ursula
T1  - Recycling systems based on screen-printed electrodes
Y1  - 1998
ER  - 
TY  - JOUR
A1  - Baeumner, Antje J.
A1  - Gauglitz, Guenter
A1  - Scheller, Frieder W.
T1  - Focus on bioanalysis
N2  - Editoria
Y1  - 2010
UR  - http://www.springerlink.com/content/100417
U6  - https://doi.org/10.1007/s00216-010-4203-9
SN  - 1618-2642
ER  - 
TY  - JOUR
A1  - Bosserdt, Maria
A1  - Gajovic-Eichelman, Nenad
A1  - Scheller, Frieder W.
T1  - Modulation of direct electron transfer of cytochrome c by use of a molecularly imprinted thin film
JF  - Analytical & bioanalytical chemistry
N2  - We describe the preparation of a molecularly imprinted polymer film (MIP) on top of a self-assembled monolayer (SAM) of mercaptoundecanoic acid (MUA) on gold, where the template cytochrome c (cyt c) participates in direct electron transfer (DET) with the underlying electrode. To enable DET, a non-conductive polymer film is electrodeposited from an aqueous solution of scopoletin and cyt c on to the surface of a gold electrode previously modified with MUA. The electroactive surface concentration of cyt c was 0.5 pmol cm(-2). In the absence of the MUA layer, no cyt c DET was observed and the pseudo-peroxidatic activity of the scopoletin-entrapped protein, assessed via oxidation of Ampliflu red in the presence of hydrogen peroxide, was only 30 % of that for the MIP on MUA. This result indicates that electrostatic adsorption of cyt c by the MUA-SAM substantially increases the surface concentration of cyt c during the electrodeposition step, and is a prerequisite for the productive orientation required for DET. After template removal by treatment with sulfuric acid, rebinding of cyt c to the MUA-MIP-modified electrode occurred with an affinity constant of 100,000 mol(-1) L, a value three times higher than that determined by use of fluorescence titration for the interaction between scopoletin and cyt c in solution. The DET of cyt c in the presence of myoglobin, lysozyme, and bovine serum albumin (BSA) reveals that the MIP layer suppresses the effect of competing proteins.
KW  - Cytochrome c
KW  - Molecularly imprinted polymer film
KW  - Mercaptoundecanoic acid
KW  - Direct electron transfer
KW  - Scopoletin (7-hydroxy-6-methoxycoumarin)
Y1  - 2013
U6  - https://doi.org/10.1007/s00216-013-7009-8
SN  - 1618-2642
VL  - 405
IS  - 20
SP  - 6437
EP  - 6444
PB  - Springer
CY  - Heidelberg
ER  - 
TY  - JOUR
A1  - Scheller, Frieder W.
T1  - New recognition elements for bioanalytics
Y1  - 1996
ER  - 
TY  - JOUR
A1  - Pfeiffer, Dorothea
A1  - Schubert, Frank
A1  - Wollenberger, Ursula
A1  - Scheller, Frieder W.
T1  - Electrochemical sensors : enzyme electrodes and field effect transistors
Y1  - 1996
ER  - 
TY  - JOUR
A1  - Wollenberger, Ursula
A1  - Scheller, Frieder W.
T1  - Enzyme activation for activator and enzyme activity measurement
Y1  - 1993
ER  - 
TY  - JOUR
A1  - Wollenberger, Ursula
A1  - Neumann, B.
A1  - Scheller, Frieder W.
T1  - Enzyme and microbial sensors for environmental Monitoring
Y1  - 1993
ER  - 
TY  - JOUR
A1  - Yarman, Aysu
A1  - Schulz, Christopher
A1  - Sygmund, Cristoph
A1  - Ludwig, Roland
A1  - Gorton, Lo
A1  - Wollenberger, Ursula
A1  - Scheller, Frieder W.
T1  - Third generation ATP sensor with enzymatic analyte recycling
JF  - Electroanalysis : an international journal devoted to fundamental and practical aspects of electroanalysis
N2  - For the first time the direct electron transfer of an enzyme - cellobiose dehydrogenase, CDH - has been coupled with the hexokinase catalyzed competition for glucose in a sensor for ATP. To enhance the signal output for ATP, pyruvate kinase was coimmobilized to recycle ADP by the phosphoenolpyruvate driven reaction. The new sensor overcomes the limit of 1:1 stoichiometry of the sequential or competitive conversion of ATP by effective enzymatic recycling of the analyte. The anodic oxidation of the glucose converting CDH proceeds at electrode potentials below 0 mV vs. Ag vertical bar AgCl thus potentially interfering substances like ascorbic acid or catecholamines do not influence the measuring signal. The combination of direct electron transfer of CDH with the enzymatic recycling results in an interference-free and oxygen-independent measurement of ATP in the lower mu molar concentration range with a lower limit of detection of 63.3 nM (S/N=3).
KW  - ATP
KW  - Third generation sensor
KW  - Enzymatic recycling
KW  - Cellobiose dehydrogenase
KW  - Hexokinase
KW  - Pyruvate kinase
Y1  - 2014
U6  - https://doi.org/10.1002/elan.201400231
SN  - 1040-0397
SN  - 1521-4109
VL  - 26
IS  - 9
SP  - 2043
EP  - 2048
PB  - Wiley-VCH
CY  - Weinheim
ER  - 
TY  - JOUR
A1  - Spricigo, Roberto
A1  - Leimkühler, Silke
A1  - Gorton, Lo
A1  - Scheller, Frieder W.
A1  - Wollenberger, Ursula
T1  - The Electrically Wired Molybdenum Domain of Human Sulfite Oxidase is Bioelectrocatalytically Active
JF  - European journal of inorganic chemistry : a journal of ChemPubSoc Europe
N2  - We report electron transfer between the catalytic molybdenum cofactor (Moco) domain of human sulfite oxidase (hSO) and electrodes through a poly(vinylpyridine)-bound [osmium(N,N'-methyl-2,2'-biimidazole)(3)](2+/3+) complex as the electron-transfer mediator. The biocatalyst was immobilized in this low-potential redox polymer on a carbon electrode. Upon the addition of sulfite to the immobilized separate Moco domain, the generation of a significant catalytic current demonstrated that the catalytic center is effectively wired and active. The bioelectrocatalytic current of the wired separate catalytic domain reached 25% of the signal of the wired full molybdoheme enzyme hSO, in which the heme b(5) is involved in the electron-transfer pathway. This is the first report on a catalytically active wired molybdenum cofactor domain. The formal potential of this electrochemical mediator is between the potentials of the two cofactors of hSO, and as hSO can occupy several conformations in the polymer matrix, it is imaginable that electron transfer from the catalytic site to the electrode through the osmium center occurs for the hSO molecules in which the Moco domain is sufficiently accessible. The observation of catalytic oxidation currents at low potentials is favorable for applications in bioelectronic devices.
KW  - Metalloenzymes
KW  - Enzyme catalysis
KW  - Immobilization
KW  - Osmium
Y1  - 2015
U6  - https://doi.org/10.1002/ejic.201500034
SN  - 1434-1948
SN  - 1099-0682
IS  - 21
SP  - 3526
EP  - 3531
PB  - Wiley-VCH
CY  - Weinheim
ER  - 
TY  - JOUR
A1  - Wu, Yunhua
A1  - Wollenberger, Ursula
A1  - Hofrichter, Martin
A1  - Ullrich, Rene
A1  - Scheibner, Katrin
A1  - Scheller, Frieder W.
T1  - Direct electron transfer of Agrocybe aegerita peroxygenase at electrodes modified with chitosan-capped Au nanoparticles and its bioelectrocatalysis to aniline
JF  - Sensors and actuators : B, Chemical
N2  - Three different sizes of chitosan-capped Au nanoparticles were synthesized and were used to incorporate Agrocybe aegerita peroxygenase (AaeAPO) onto the surface of glassy carbon electrode. The direct electron transfer of AaeAPO was achieved in all films. The highest amount of electroactive enzyme and highest electron transfer rate constant k(s) of AaeAPO were obtained in the film with the smallest size of chitosan-capped Au nanoparticles.
 In anaerobic solutions, quasi-reversible oxidation and reduction are obtained with a formal potential of -0.280V vs. Ag/AgCl 1 M KCl in 100 mM (pH 7.0) PBS at scan rate of 1 V s(-1). Bioelectrocatalytic reduction currents can be obtained with the AaeAPO-modified electrode on addition of hydrogen peroxide. This reaction was suppressed when sodium azide, an inhibitor of AaeAPO, was present. Furthermore, the peroxide-dependent conversion of aniline was characterized and it was found that a polymer product via p-aminophenol is formed. And the AaeAPO biosensor was applied to determine aniline and p-aminophenol.
KW  - Agrocybe aegerita peroxygenase
KW  - Au nanoparticles
KW  - Direct electron transfer
KW  - Aniline biosensor
KW  - Bioelectrocatalysis
Y1  - 2011
U6  - https://doi.org/10.1016/j.snb.2011.09.090
SN  - 0925-4005
VL  - 160
IS  - 1
SP  - 1419
EP  - 1426
PB  - Elsevier
CY  - Lausanne
ER  - 
TY  - JOUR
A1  - Yarman, Aysu
A1  - Badalyan, Artavazd
A1  - Gajovic-Eichelmann, Nenad
A1  - Wollenberger, Ursula
A1  - Scheller, Frieder W.
T1  - Enzyme electrode for aromatic compounds exploiting the catalytic activities of microperoxidase-11
JF  - Biosensors and bioelectronics : the principal international journal devoted to research, design development and application of biosensors and bioelectronics
N2  - Microperoxidase-11 (MR-11) which has been immobilised in a matrix of chitosan-embedded gold nanoparticles on the surface of a glassy carbon electrode catalyzes the conversion of aromatic substances. This peroxide-dependent catalysis of microperoxidase has been applied in an enzyme electrode for the first time to indicate aromatic compounds such as aniline. 4-fluoroaniline, catechol and p-aminophenol. The electrode signal is generated by the cathodic reduction of the quinone or quinoneimine which is formed in the presence of both MP-II and peroxide from the substrate. The same sensor principle will be extended to aromatic drugs.
KW  - Microperoxidase-11
KW  - Nanoparticles
KW  - p-Aminophenol
KW  - Aniline
KW  - Catechol
KW  - 4-Fluoroaniline
KW  - Biosensors
Y1  - 2011
U6  - https://doi.org/10.1016/j.bios.2011.09.004
SN  - 0956-5663
VL  - 30
IS  - 1
SP  - 320
EP  - 323
PB  - Elsevier
CY  - Oxford
ER  - 
TY  - JOUR
A1  - Peng, Lei
A1  - Utesch, Tillmann
A1  - Yarman, Aysu
A1  - Jeoung, Jae-Hun
A1  - Steinborn, Silke
A1  - Dobbek, Holger
A1  - Mroginski, Maria Andrea
A1  - Tanne, Johannes
A1  - Wollenberger, Ursula
A1  - Scheller, Frieder W.
T1  - Surface-Tuned Electron Transfer and Electrocatalysis of Hexameric Tyrosine-Coordinated Heme Protein
JF  - Chemistry - a European journal
N2  - Molecular modeling, electrochemical methods, and quartz crystal microbalance were used to characterize immobilized hexameric tyrosine-coordinated heme protein (HTHP) on bare carbon or on gold electrodes modified with positively and negatively charged self-assembled monolayers (SAMs), respectively. HTHP binds to the positively charged surface but no direct electron transfer (DET) is found due to the long distance of the active sites from the electrode surfaces. At carboxyl-terminated surfaces, the neutrally charged bottom of HTHP can bind to the SAM. For this "disc" orientation all six hemes are close to the electrode and their direct electron transfer should be efficient. HTHP on all negatively charged SAMs showed a quasi-reversible redox behavior with rate constant k(s) values between 0.93 and 2.86 s(-1) and apparent formal potentials E-app(0)' between -131.1 and -249.1 mV. On the MUA/MU-modified electrode, the maximum surface concentration corresponds to a complete monolayer of the hexameric HTHP in the disc orientation. HTHP electrostatically immobilized on negatively charged SAMs shows electrocatalysis of peroxide reduction and enzymatic oxidation of NADH.
KW  - electrochemistry
KW  - electron transfer
KW  - heme proteins
KW  - molecular modeling
KW  - monolayers
Y1  - 2015
U6  - https://doi.org/10.1002/chem.201405932
SN  - 0947-6539
SN  - 1521-3765
VL  - 21
IS  - 20
SP  - 7596
EP  - 7602
PB  - Wiley-VCH
CY  - Weinheim
ER  - 
TY  - JOUR
A1  - Jetzschmann, Katharina J.
A1  - Jagerszki, Gyula
A1  - Dechtrirat, Decha
A1  - Yarman, Aysu
A1  - Gajovic-Eichelmann, Nenad
A1  - Gilsing, Hans-Detlev
A1  - Schulz, Burkhard
A1  - Gyurcsanyi, Robert E.
A1  - Scheller, Frieder W.
T1  - Vectorially Imprinted Hybrid Nanofilm for Acetylcholinesterase Recognition
JF  - Advanced functional materials
N2  - Effective recognition of enzymatically active tetrameric acetylcholinesterase (AChE) is accomplished by a hybrid nanofilm composed of a propidium-terminated self-assembled monolayer (Prop-SAM) which binds AChE via its peripheral anionic site (PAS) and an ultrathin electrosynthesized molecularly imprinted polymer (MIP) cover layer of a novel carboxylate-modified derivative of 3,4-propylenedioxythiophene. The rebinding of the AChE to the MIP/Prop-SAM nanofilm covered electrode is detected by measuring in situ the enzymatic activity. The oxidative current of the released thiocholine is dependent on the AChE concentration from approximate to 0.04 x 10(-6) to 0.4 x 10(-6)m. An imprinting factor of 9.9 is obtained for the hybrid MIP, which is among the best values reported for protein imprinting. The dissociation constant characterizing the strength of the MIP-AChE binding is 4.2 x 10(-7)m indicating the dominant role of the PAS-Prop-SAM interaction, while the benefit of the MIP nanofilm covering the Prop-SAM layer is the effective suppression of the cross-reactivity toward competing proteins as compared with the Prop-SAM. The threefold selectivity gain provided by i) the shape-specific MIP filter, ii) the propidium-SAM, iii) signal generation only by the AChE bound to the nanofilm shows promise for assessing AChE activity levels in cerebrospinal fluid.
KW  - acetylcholinesterase
KW  - biomimetic sensors
KW  - molecularly imprinted electropolymers
KW  - peripheral anionic site
KW  - propidium
Y1  - 2015
U6  - https://doi.org/10.1002/adfm.201501900
SN  - 1616-301X
SN  - 1616-3028
VL  - 25
IS  - 32
SP  - 5178
EP  - 5183
PB  - Wiley-VCH
CY  - Weinheim
ER  - 
TY  - JOUR
A1  - Yarman, Aysu
A1  - Nagel, Thomas
A1  - Gajovic-Eichelmann, Nenad
A1  - Fischer, Anna
A1  - Wollenberger, Ursula
A1  - Scheller, Frieder W.
T1  - Bioelectrocatalysis by Microperoxidase-11 in a Multilayer Architecture of Chitosan Embedded Gold Nanoparticles
JF  - Electroanalysis : an international journal devoted to fundamental and practical aspects of electroanalysis
N2  - We report on the redox behaviour of the microperoxidase-11 (MP-11) which has been electrostatically immobilized in a matrix of chitosan-embedded gold nanoparticles on the surface of a glassy carbon electrode. MP-11 contains a covalently bound heme c as the redox active group that exchanges electrons with the electrode via the gold nanoparticles. Electroactive surface concentration of MP-11 at high scan rate is between 350+/-50 pmol cm(-2), which reflects a multilayer process. The formal potential (E degrees') of MP-11 in the gold nanoparticles-chitosan film was estimated to be -(267.7+/-2.9) mV at pH 7.0. The heterogeneous electron transfer rate constant (k(s)) starts at 1.21 s(-1) and levels off at 6.45 s(-1) in the scan rate range from 0.1 to 2.0 V s(-1). Oxidation and reduction of MP-11 by hydrogen peroxide and superoxide, respectively have been coupled to the direct electron transfer of MP-11.
KW  - Microperoxidase
KW  - Direct electron transfer
KW  - Nanoparticles
KW  - Hydrogen peroxide
KW  - Superoxide
KW  - Bioelectrocatalysis
Y1  - 2011
U6  - https://doi.org/10.1002/elan.201000535
SN  - 1040-0397
VL  - 23
IS  - 3
SP  - 611
EP  - 618
PB  - Wiley-Blackwell
CY  - Malden
ER  - 
TY  - JOUR
A1  - Yarman, Aysu
A1  - Scheller, Frieder W.
T1  - The first electrochemical MIP sensor for tamoxifen
JF  - Sensors
N2  - We present an electrochemical MIP sensor for tamoxifen (TAM)-a nonsteroidal anti-estrogen-which is based on the electropolymerisation of an O-phenylenediamine. resorcinol mixture directly on the electrode surface in the presence of the template molecule. Up to now only. bulk. MIPs for TAM have been described in literature, which are applied for separation in chromatography columns. Electro-polymerisation of the monomers in the presence of TAM generated a film which completely suppressed the reduction of ferricyanide. Removal of the template gave a markedly increased ferricyanide signal, which was again suppressed after rebinding as expected for filling of the cavities by target binding. The decrease of the ferricyanide peak of the MIP electrode depended linearly on the TAM concentration between 1 and 100 nM. The TAM-imprinted electrode showed a 2.3 times higher recognition of the template molecule itself as compared to its metabolite 4-hydroxytamoxifen and no cross-reactivity with the anticancer drug doxorubucin was found. Measurements at + 1.1 V caused a fouling of the electrode surface, whilst pretreatment of TAM with peroxide in presence of HRP generated an oxidation product which was reducible at 0 mV, thus circumventing the polymer formation and electrochemical interferences.
KW  - molecularly imprinted polymers
KW  - anticancer drug
KW  - tamoxifen
KW  - electropolymerisation
Y1  - 2014
U6  - https://doi.org/10.3390/s140507647
SN  - 1424-8220
VL  - 14
IS  - 5
SP  - 7647
EP  - 7654
PB  - MDPI
CY  - Basel
ER  - 
TY  - JOUR
A1  - Neumann, Bettina
A1  - Yarman, Aysu
A1  - Wollenberger, Ursula
A1  - Scheller, Frieder W.
T1  - Characterization of the enhanced peroxidatic activity of amyloid beta peptide-hemin complexes towards neurotransmitters
JF  - Analytical & bioanalytical chemistry
N2  - Binding of heme to the amyloid peptides A beta 40/42 is thought to be an initial step in the development of symptoms in the early stages of Alzheimer's disease by enhancing the intrinsic peroxidatic activity of heme. We found considerably higher acceleration of the reaction for the physiologically relevant neurotransmitters dopamine and serotonin than reported earlier for the artificial substrate 3,3',5,5'-tetramethylbenzidine (TMB). Thus, the binding of hemin to A beta peptides might play an even more crucial role in the early stages of Alzheimer's disease than deduced from these earlier results. To mimic complex formation, a new surface architecture has been developed: The interaction between the truncated amyloid peptide A beta 1-16 and hemin immobilized on an aminohexanethiol spacer on a gold electrode has been analyzed by cyclic voltammetry. The resulting complex has a redox pair with a 25 mV more cathodic formal potential than hemin alone.
KW  - Peroxidatic activity
Y1  - 2014
U6  - https://doi.org/10.1007/s00216-014-7822-8
SN  - 1618-2642
SN  - 1618-2650
VL  - 406
IS  - 14
SP  - 3359
EP  - 3364
PB  - Springer
CY  - Heidelberg
ER  - 
TY  - JOUR
A1  - Yarman, Aysu
A1  - Gröbe, Glenn
A1  - Neumann, Bettina
A1  - Kinne, Mathias
A1  - Gajovic-Eichelmann, Nenad
A1  - Wollenberger, Ursula
A1  - Hofrichter, Martin
A1  - Ullrich, Rene
A1  - Scheibner, Katrin
A1  - Scheller, Frieder W.
T1  - The aromatic peroxygenase from Marasmius rutola-a new enzyme for biosensor applications
JF  - Analytical & bioanalytical chemistry
N2  - The aromatic peroxygenase (APO; EC 1.11.2.1) from the agraric basidomycete Marasmius rotula (MroAPO) immobilized at the chitosan-capped gold-nanoparticle-modified glassy carbon electrode displayed a pair of redox peaks with a midpoint potential of -278.5 mV vs. AgCl/AgCl (1 M KCl) for the Fe(2+)/Fe(3+) redox couple of the heme-thiolate-containing protein. MroAPO oxidizes aromatic substrates such as aniline, p-aminophenol, hydroquinone, resorcinol, catechol, and paracetamol by means of hydrogen peroxide. The substrate spectrum overlaps with those of cytochrome P450s and plant peroxidases which are relevant in environmental analysis and drug monitoring. In M. rotula peroxygenase-based enzyme electrodes, the signal is generated by the reduction of electrode-active reaction products (e.g., p-benzoquinone and p-quinoneimine) with electro-enzymatic recycling of the analyte. In these enzyme electrodes, the signal reflects the conversion of all substrates thus representing an overall parameter in complex media. The performance of these sensors and their further development are discussed.
KW  - Unspecific peroxygenase
KW  - Cytochrome P450
KW  - Biosensors
KW  - Phenolic substances
Y1  - 2012
U6  - https://doi.org/10.1007/s00216-011-5497-y
SN  - 1618-2642
VL  - 402
IS  - 1
SP  - 405
EP  - 412
PB  - Springer
CY  - Heidelberg
ER  -