TY - JOUR A1 - Scheller, Frieder W. A1 - Scheller, A. T1 - Bi-Enzymelektrode zur Messung von Sorbitol in pharmazeutischen Produkten Y1 - 1996 ER - TY - JOUR A1 - Vijgenboom, E. A1 - Vijgenboom, E. A1 - Teppner, A. W. J. W. A1 - Makower, Alexander A1 - Scheller, Frieder W. A1 - Canters, Gerard W. A1 - Wollenberger, Ursula T1 - Determination of phenolic compounds using recombinant tyrosinanse from Streptomyces antibioticus Y1 - 2001 ER - TY - JOUR A1 - Buttermeyer, R. A1 - Philipp, A. W. A1 - Mall, J. W. A1 - Ge, Bixia A1 - Scheller, Frieder W. A1 - Lisdat, Fred T1 - In vivo measurement of oxygen derived free radicals during reperfusion injury Y1 - 2002 ER - TY - JOUR A1 - Mak, Karen K. W. A1 - Wollenberger, Ursula A1 - Scheller, Frieder W. A1 - Renneberg, Reinhard T1 - An amperometric bi-enzyme sensor for determination of formate using cofactor regeneration Y1 - 2003 ER - TY - JOUR A1 - Nießner, Reinhard A1 - Broekaert, J. A1 - Einax, J. W. A1 - Scheller, Frieder W. A1 - Stöcklein, Walter F. M. T1 - Trendbericht analytische Biochemie 2000/2001 Y1 - 2002 ER - TY - JOUR A1 - Bauer, Christian G. A1 - Eremenko, A. V. A1 - Ehrentreich-Förster, Eva A1 - Bier, Frank Fabian A1 - Makower, Alexander A1 - Halsall, H. B. A1 - Heineman, W. R. A1 - Scheller, Frieder W. T1 - Zeptomole-detecting biosensor for alkaline phosphatase in an electroche mical immunoassay for 2,4- dichlorophenoacetic acid Y1 - 1996 ER - TY - JOUR A1 - Freaney, R. A1 - MacShane, A. A1 - Keaveny, T. V. A1 - MacKenna, M. A1 - Rabenstein, K. A1 - Scheller, Frieder W. A1 - Pfeiffer, Dorothea A1 - Urban, G. A1 - Moser, I. A1 - Jobst, G. A1 - Manz, A. A1 - Verpoorte, E. A1 - Widmer, M. W. A1 - Diamond, D. A1 - Dempsey, E. A1 - deViteri, F. J. S. A1 - Smyth, M. T1 - Novel instrumentation for real-time monitoring using miniaturized flow systems with integrated biosensors Y1 - 1997 ER - TY - JOUR A1 - Welzel, H.-P. A1 - Kossmehl, G. A1 - Engelmann, G. A1 - Neumann, B. A1 - Wollenberger, Ursula A1 - Scheller, Frieder W. A1 - Schröder, W. T1 - Reactive groups on polymer covered electrodes, 4. Lactate-oxidase-biosensor based on electrodes modifies by polyphiophene Y1 - 1996 ER - TY - JOUR A1 - Stöcklein, Walter F. M. A1 - Behrsing, Olaf A1 - Scharte, Gudrun A1 - Micheel, Burkhard A1 - Benkert, Alexander A1 - Schössler, W. A1 - Warsinke, Axel A1 - Scheller, Frieder W. T1 - Enzyme kinetic assays with surface plasmon resonance (BIAcore) based on competition between enzyme and creatinine antibody Y1 - 2000 ER - TY - JOUR A1 - Gajovic, Nenad A1 - Habermüller, K. A1 - Warsinke, Axel A1 - Schuhmann, W. A1 - Scheller, Frieder W. T1 - A pyruvate oxidase electrode based on an electrochemically deposited redox polymer Y1 - 1999 ER - TY - JOUR A1 - Jin, Wen A1 - Wollenberger, Ursula A1 - Kärgel, E. A1 - Schunck, W.-H. A1 - Scheller, Frieder W. T1 - Electrochemical investigation of the intermolecular electron transfer between cytochrome c and NADPH-cytochrome P450-reductase Y1 - 1997 ER - TY - JOUR A1 - Neumann, Bettina A1 - Götz, Robert A1 - Wrzolek, Pierre A1 - Scheller, Frieder W. A1 - Weidinger, Inez M. A1 - Schwalbe, Matthias A1 - Wollenberger, Ulla T1 - Enhancement of the Electrocatalytic Activity of Thienyl-Substituted Iron Porphyrin Electropolymers by a Hangman Effect JF - ChemCatChem : heterogeneous & homogeneous & bio- & nano-catalysis ; a journal of ChemPubSoc Europe N2 - The thiophene-modified iron porphyrin FeT3ThP and the respective iron Hangman porphyrin FeH3ThP, incorporating a carboxylic acid hanging group in the second coordination sphere of the iron center, were electropolymerized on glassy carbon electrodes using 3,4-ethylenedioxythiophene (EDOT) as co-monomer. Scanning electron microscopy images and Resonance Raman spectra demonstrated incorporation of the porphyrin monomers into a fibrous polymer network. Porphyrin/polyEDOT films catalyzed the reduction of molecular oxygen in a four-electron reaction to water with onset potentials as high as +0.14V vs. Ag/AgCl in an aqueous solution of pH7. Further, FeT3ThP/polyEDOT films showed electrocatalytic activity towards reduction of hydrogen peroxide at highly positive potentials, which was significantly enhanced by introduction of the carboxylic acid hanging group in FeH3ThP. The second coordination sphere residue promotes formation of a highly oxidizing reaction intermediate, presumably via advantageous proton supply, as observed for peroxidases and catalases making FeH3ThP/polyEDOT films efficient mimics of heme enzymes. KW - activation of oxygen species KW - electro-polymerization KW - Hangman porphyrin KW - heterogeneous catalysis KW - immobilization Y1 - 2018 U6 - https://doi.org/10.1002/cctc.201800934 SN - 1867-3880 SN - 1867-3899 VL - 10 IS - 19 SP - 4353 EP - 4361 PB - Wiley-VCH CY - Weinheim ER - TY - JOUR A1 - Ozcelikay, Goksu A1 - Kurbanoglu, Sevinc A1 - Zhang, Xiaorong A1 - Söz, Çağla Kosak A1 - Wollenberger, Ulla A1 - Ozkan, Sibel A. A1 - Yarman, Aysu A1 - Scheller, Frieder W. T1 - Electrochemical MIP Sensor for Butyrylcholinesterase JF - Polymers N2 - Molecularly imprinted polymers (MIPs) mimic the binding sites of antibodies by substituting the amino acid-scaffold of proteins by synthetic polymers. In this work, the first MIP for the recognition of the diagnostically relevant enzyme butyrylcholinesterase (BuChE) is presented. The MIP was prepared using electropolymerization of the functional monomer o-phenylenediamine and was deposited as a thin film on a glassy carbon electrode by oxidative potentiodynamic polymerization. Rebinding and removal of the template were detected by cyclic voltammetry using ferricyanide as a redox marker. Furthermore, the enzymatic activity of BuChE rebound to the MIP was measured via the anodic oxidation of thiocholine, the reaction product of butyrylthiocholine. The response was linear between 50 pM and 2 nM concentrations of BuChE with a detection limit of 14.7 pM. In addition to the high sensitivity for BuChE, the sensor responded towards pseudo-irreversible inhibitors in the lower mM range. KW - molecularly imprinted polymers KW - biomimetic sensors KW - butyrylcholinesterase KW - o-phenylenediamine KW - rivastigmine Y1 - 2019 U6 - https://doi.org/10.3390/polym11121970 SN - 2073-4360 VL - 11 IS - 12 PB - MDPI CY - Basel ER - TY - JOUR A1 - Nitsche, Andreas A1 - Kurth, Andreas A1 - Dunkhorst, Anna A1 - Pänke, Oliver A1 - Sielaff, Hendrik A1 - Junge, Wolfgang A1 - Muth, Doreen A1 - Scheller, Frieder W. A1 - Stöcklein, Walter F. M. A1 - Pauli, Georg A1 - Kage, Andreas T1 - One-step selection of vaccinia virus binding DNA-aptamers by MonoLEX Y1 - 2007 UR - http://www.biomedcentral.com/1472-6750/7 U6 - https://doi.org/10.1186/1472-6750-7-48 ER - TY - JOUR A1 - Kapp, Andreas A1 - Beissenhirtz, Moritz Karl A1 - Geyer, F. A1 - Scheller, Frieder W. A1 - Viezzoli, Maria Silvia A1 - Lisdat, Fred T1 - Electrochemical and sensorial behaviour of SOD mutants immobilized on gold electrodes in aqueous / organic solvent mixtures Y1 - 2006 UR - http://www3.interscience.wiley.com/cgi-bin/jhome/26571/ U6 - https://doi.org/10.1002/elan.200603620 SN - 1040-0397 ER - TY - JOUR A1 - Liu, Songqin A1 - Wollenberger, Ursula A1 - Katterle, Martin A1 - Scheller, Frieder W. T1 - Ferroceneboronic acid-based amperometric biosensor for glycated hemoglobin N2 - An amperometric biosensor for the determination of glycated hemoglobin in human whole blood is proposed. The principle is based on the electrochemical measurement of ferroceneboronic acid (FcBA) that has been specifically bound to the glycated N-terminus. Hemoglobin is immobilized on a zirconium dioxide nanoparticle modified pyrolytic graphite electrode (PGE) in the presence of didodecyldimethylammonium bromide (DDAB). The incubation of this sensor in FcBA solution leads to the formation of an FcBA-modified surface due to the affinity interaction between boronate and the glycated sites of the hemoglobin. The binding of FcBA results in well-defined redox peaks with an E-0' of 0.299 V versus Ag/AgCl (1 M KCl). The square wave voltammetric response of the bound FcBA reflects the amount of glycated hemoglobin at the surface. This signal increases linearily with the degree of glycated hemoglobin from 6.8 to 14.0% of total immobilized hemoglobin. The scheme was applied to the determination of the fraction of glycated hemoglobin in whole blood samples. Y1 - 2006 UR - http://www.sciencedirect.com/science/journal/09254005 U6 - https://doi.org/10.1016/j.snb.2005.07.011 SN - 0925-4005 ER - TY - JOUR A1 - Beissenhirtz, Moritz Karl A1 - Scheller, Frieder W. A1 - Viezzoli, Maria Silvia A1 - Lisdat, Fred T1 - Engineered superoxide dismutase monomers for superoxide biosensor applications N2 - Because of its high reaction rate and specificity, the enzyme superoxide dismutase (SOD) offers great potential for the sensitive quantification of superoxide radicals in electrochemical biosensors. In this work, monomeric mutants of human Cu,Zn-SOD were engineered to contain one or two additional cysteine residues, which could be used to bind the protein to gold surfaces, thus making the use of promotor molecules unnecessary. Six mutants were successfully designed, expressed, and purified. All mutants bound directly to unmodified gold surfaces via the sulfur of the cysteine residues and showed a quasireversible, direct electron transfer to the electrode. Thermodynamic and kinetic parameters of the electron transfer were characterized and showed only slight variations between the individual mutants. For one of the mutants, the interaction with the superoxide radical was studied in more detail. For both partial reactions of the dismutation, an interaction between protein and radical could be shown. In an amperometric biosensorial approach, the SOD-mutant electrode was successfully applied for the detection of superoxide radicals. In the oxidation region, the electrode surpassed the sensitivity of the commonly used cytochrome c electrodes by similar to 1 order of magnitude while not being limited by interferences, but the electrode did not fully reach the sensitivity of dimeric Cu,Zn-SOD immobilized on MPA-modified gold Y1 - 2006 UR - http://pubs.acs.org/journal/ancham U6 - https://doi.org/10.1021/Ac051465g SN - 0003-2700 ER - TY - JOUR A1 - Halamek, Jan A1 - Teller, Carsten A1 - Makower, Alexander A1 - Fournier, Didier A1 - Scheller, Frieder W. T1 - EQCN-based cholinesterase biosensors N2 - The binding of acetylcholinesterase (AChE) to a propidium-modified piezoelectric quartz crystal and its surface enzymatic activity have been investigated. Propidium binds to a site remote to the active center of AChE - the peripheral anionic site (PAS) - which is located on the rim of the gorge to the active site. The gold electrodes of the quartz crystal were first modified with 11-mercaptoundecanoic acid to which propidium was coupled. AChE binding was monitored by a quartz crystal nanobalance (QCN), followed by amperometric activity evaluation of the AChE loaded on the sensor. Interestingly, the binding is strong but does not inhibit AChE. However, an excess of propidium in solution inhibits the immobilized enzyme. The surface enzymatic activities observed depend on the amount of enzyme and differ according to the type and species, i.e. number of enzyme subunits (Electrophorus electricus tetrameric, Drosophila melanogaster mono- and dimeric form - DmAChE). The operational stability and regeneration, effect of propidium in solution and detection limit for substrate for various AChEs were investigated amperometrically. Y1 - 2006 UR - http://www.sciencedirect.com/science/journal/00134686 U6 - https://doi.org/10.1016/j.electacta.2006.03.047 SN - 0013-4686 ER - TY - JOUR A1 - Lettau, Kristian A1 - Warsinke, Axel A1 - Katterle, Martin A1 - Danielsson, Bengt A1 - Scheller, Frieder W. T1 - A bifunctional molecularly imprinted polymer (MIP): analysis of binding and catalysis by a thermistor N2 - Binding or catalysis? Both can be distinguished with a molecularly imprinted polymer (MIP) by the different patterns of heat generation. The catalytically active sites, like in the corresponding enzyme, generate a steady-state temperature increase. Thus, enzyme-like catalysis and antibody-analogue binding are analyzed simultaneously in a bifunctional MIP for the first time (see scheme). Y1 - 2006 UR - http://www3.interscience.wiley.com/cgi-bin/jhome/26737/ U6 - https://doi.org/10.1002/anie.200601796 ER - TY - JOUR A1 - Bistolas, Nikitas A1 - Wollenberger, Ursula A1 - Jung, Christiane A1 - Scheller, Frieder W. T1 - Cytochrome P450 biosensors : a review N2 - Cytochrome P450 (CYP) is a large family of enzymes containing heme as the active site. Since their discovery and the elucidation of their structure, they have attracted the interest of scientist for many years, particularly due to their catalytic abilities. Since the late 1970s attempts have concentrated on the construction and development of electrochemical sensors. Although sensors based on mediated electron transfer have also been constructed, the direct electron transfer approach has attracted most of the interest. This has enabled the investigation of the electrochemical properties of the various isoforms of CYP. Furthermore, CYP utilized to construct biosensors for the determination of substrates important in environmental monitoring, pharmaceutical industry and clinical practice. (c) 2004 Elsevier B. V. All rights reserved Y1 - 2005 ER -