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 - 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 - 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 - 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 - Lehmann, Claudia A1 - Wollenberger, Ursula A1 - Brigelius-Flohé, Regina A1 - Scheller, Frieder W. T1 - Bioelectrocatalysis by a selenoenzyme Y1 - 1998 ER - TY - JOUR A1 - Lisdat, Fred A1 - Wollenberger, Ursula A1 - Paeschke, Manfred A1 - Scheller, Frieder W. T1 - Sensitive catecholamine measurement using a monoenzymatic recycling system Y1 - 1998 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 - 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 - Barmin, Anatoli V. A1 - Eremenko, Arkadi V. A1 - Osipova, T. A1 - Kurochkin, Iliya A1 - Makower, Alexander A1 - Scheller, Frieder W. T1 - Affinyi fermentometrischeskii analis ingibitorov cholinestarasi Y1 - 1999 ER - TY - JOUR A1 - Kleinjung, Frank A1 - Ehrentreich-Förster, Eva A1 - Scheller, Frieder W. T1 - Changing functionality of surfaces by directed self-assembly using oligonucleotides - the oligo-tag Y1 - 1999 ER - TY - JOUR A1 - Bauer, Christian G. A1 - Kühn, A. A1 - Gajovic, Nenad A1 - Skorobogatko, O. V. A1 - Holt, P. J. A1 - Bruce, N. C. A1 - Makower, Alexander A1 - Lowe, Ch. R. A1 - Scheller, Frieder W. T1 - New enzymen sensors for morphine and codeine based on morphine dehydrogenase and laccase Y1 - 1999 ER - TY - JOUR A1 - Gajovic, Nenad A1 - Warsinke, Axel A1 - Huang, T. A1 - Schulmeister, Thomas A1 - Scheller, Frieder W. T1 - Characterization and mathematical modelling of a novel bienzyme electrode for L-malate with cofactor recycling Y1 - 1999 ER - TY - JOUR A1 - Lisdat, Fred A1 - Ge, Bixia A1 - Ehrentreich-Förster, Eva A1 - Reszka, R. A1 - Scheller, Frieder W. T1 - SOD activity measurement using cytochrome c modified electrode Y1 - 1999 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 - Lisdat, Fred A1 - Ge, Bixia A1 - Scheller, Frieder W. T1 - Oligonucleotide-modified electrodes for fast electron transfer to cytochrome c Y1 - 1999 ER - TY - JOUR A1 - Huang, T. A1 - Warsinke, Axel A1 - Koroljova-Skorobogatko, O. V. A1 - Makower, Alexander A1 - Kuwana, T. A1 - Scheller, Frieder W. T1 - A bienzyme carbon paste electrode for the sensitive detection of NADPH and the measurement of glucose-6- phosphate dehydrogenase Y1 - 1999 ER - TY - JOUR A1 - Lei, Chenghong A1 - Lisdat, Fred A1 - Wollenberger, Ursula A1 - Scheller, Frieder W. T1 - Cytochrome c : Clay-modified electrode Y1 - 1999 ER - TY - JOUR A1 - Scheller, Frieder W. A1 - Jin, Wen A1 - Ehrentreich-Förster, Eva A1 - Ge, Bixia A1 - Lisdat, Fred A1 - Büttemeyer, R. A1 - Wollenberger, Ursula T1 - Cytochrome c based superoxide sensor for in vivo application Y1 - 1999 ER - TY - JOUR A1 - Scheller, Frieder W. T1 - Deutliche Signale setzen [Leitartikel] Y1 - 1999 ER - TY - JOUR A1 - Stöcklein, Walter F. M. A1 - Rohde, M. A1 - Scharte, Gudrun A1 - Behrsing, Olaf A1 - Warsinke, Axel A1 - Micheel, Burkhard A1 - Scheller, Frieder W. T1 - Sensitive detection of triazine and phenylurea pesticides in pure organic solvent by enzyme linked immunsorbent assay (ELISA): stabilities, solubilities and sensitives Y1 - 2000 ER - TY - JOUR A1 - Ju, Huangxian A1 - Liu, Songqin A1 - Ge, Bixia A1 - Lisdat, Fred A1 - Scheller, Frieder W. T1 - Electrochemistry of cytochrome c immobilized on colloidal gold modified carbon paste electrodes and its electrocatalytic activity Y1 - 2000 ER - TY - JOUR A1 - Lisdat, Fred A1 - Ge, Bixia A1 - Stöcklein, Walter F. M. A1 - Scheller, Frieder W. A1 - Meyer, T. T1 - Electrochemical behaviour and nitric oxides interaction of immobilised cytochrome c from Rhodocyclus gelatinosus Y1 - 2000 ER - TY - JOUR A1 - Chen, Jian A1 - Wollenberger, Ursula A1 - Lisdat, Fred A1 - Ge, Bixia A1 - Scheller, Frieder W. T1 - Superoxide sensor based on hemin modified electrode Y1 - 2000 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 - Scheller, Frieder W. T1 - Biosensor-Stabilität Y1 - 2000 ER - TY - JOUR A1 - Scheller, Frieder W. T1 - Biomolekulare Erkennungssysteme für die Biochemische Analytik Y1 - 2000 ER - TY - JOUR A1 - Gajovic, Nenad A1 - Binyamin, Gary A1 - Warsinke, Axel A1 - Scheller, Frieder W. A1 - Heller, A. T1 - Operation of a miniature redox hydrogel-based pyruvate sensor in undiluted deoxygenated calf serum Y1 - 2000 ER - TY - JOUR A1 - Warsinke, Axel A1 - Benkert, Alexander A1 - Scheller, Frieder W. T1 - Electrochemical immunoassays Y1 - 2000 ER - TY - JOUR A1 - Chen, Ziping A1 - Warsinke, Axel A1 - Gajovic, Nenad A1 - Große, St. A1 - Hu, J. A1 - Kleber, H.-P. A1 - Scheller, Frieder W. T1 - A D-carnitine dehydrogenase electrode for the assessment of enantiomeric purity of L-carnitine preparations Y1 - 2000 ER - TY - JOUR A1 - Lisdat, Fred A1 - Scheller, Frieder W. T1 - Principles of sensorial radical detection - a minireview Y1 - 2000 ER - TY - JOUR A1 - Lei, Chenghong A1 - Wollenberger, Ursula A1 - Jung, Christiane A1 - Scheller, Frieder W. T1 - Clay-bridged electron transfer between cytochrome P450(cam) and electrode Y1 - 2000 ER - TY - JOUR A1 - Lei, Chenghong A1 - Wollenberger, Ursula A1 - Scheller, Frieder W. T1 - Clay based direct electrochemistry of myoglobin Y1 - 2000 ER - TY - JOUR A1 - Makower, Alexander A1 - Barmin, Anatoli V. A1 - Scheller, Frieder W. T1 - Eine neue Methode zur hochempfindlichen Analyse von Pestiziden Y1 - 2000 ER - TY - JOUR A1 - Fridman, Vadim A1 - Wollenberger, Ursula A1 - Bogdanovskaya, V. A. A1 - Lisdat, Fred A1 - Ruzgas, T. A1 - Lindgren, A. A1 - Gorton, Lo A1 - Scheller, Frieder W. T1 - Electrochemical investigation of cellobiose oxidation by cellobiose dehydrogenase in the presence of cytochrome c as mediator Y1 - 2000 ER - TY - JOUR A1 - Scheller, Frieder W. A1 - Pfeiffer, Dorothea T1 - Biosensor-Technologie in der Medizin und den Biowissenschaften Y1 - 2000 ER - TY - JOUR A1 - Lisdat, Fred A1 - Scheller, Frieder W. T1 - Technical principles. Electrodes Y1 - 2000 SN - 90-5702-447-7 ER - TY - JOUR A1 - Scheller, Frieder W. T1 - Biosensoren auf dem Weg zur Biochip-Technologie Y1 - 2001 UR - http://bisc.ch/de/focus_bioelektronik_1_d.pdf ER - TY - JOUR A1 - Schmidt, Peter Michael A1 - Matthes, E. A1 - Scheller, Frieder W. A1 - Bier, Frank Fabian T1 - Nachweis der Telomeraseaktivität in Zellkulturen mittels eines faseroptischen Sensors Y1 - 2001 ER - TY - JOUR A1 - Scheller, Frieder W. T1 - Biomoleküle als Reporter in der Analytik : keine Forschung im Elfenbeinturm Y1 - 2001 ER - TY - JOUR A1 - Ignatov, S. A1 - Ge, Bixia A1 - Scheller, Frieder W. A1 - Lisdat, Fred T1 - Detection of the antioxidant activity detection of flavonoids by using superoxide sensor Y1 - 2001 SN - 1-58603-164-3 ER - TY - JOUR A1 - Hock, Bertold A1 - Scheller, Frieder W. T1 - Conclusions and outlook Y1 - 2001 ER - TY - JOUR A1 - Lisdat, Fred A1 - Utepbergenov, D. A1 - Haseloff, R. F. A1 - Blasig, Ingolf E. A1 - Stöcklein, Walter F. M. A1 - Scheller, Frieder W. A1 - Brigelius-Flohé, Regina T1 - An optical method for the detection of oxidative stress using protein-RNA interaction Y1 - 2001 ER - TY - JOUR A1 - Lehmann, Claudia A1 - Wollenberger, Ursula A1 - Brigelius-Flohé, Regina A1 - Scheller, Frieder W. T1 - Modified gold electrodes for electrochemical studies of the reaction phospholipid hydroperoxide glutathione peroxidas with glutathione and glutathione disulfide Y1 - 2001 ER - TY - JOUR A1 - Scheller, Frieder W. A1 - Bauer, Christian G. A1 - Markower, Alexander A1 - Wollenberger, Ursula A1 - Warsinke, Axel A1 - Bier, Frank Fabian T1 - Coupling of immunoassays with enzymatic recycling electrodes Y1 - 2001 ER - TY - JOUR A1 - Lisdat, Fred A1 - Ge, Bixia A1 - Krause, B. A1 - Ehrlich, A. A1 - Bienert, H. A1 - Scheller, Frieder W. T1 - Nucleic acid-promoted electron transfer to cytochrome c Y1 - 2001 ER - TY - JOUR A1 - Lisdat, Fred A1 - Ge, Bixia A1 - Meyerhoff, M. E. A1 - Scheller, Frieder W. T1 - Signal chains with cytochromes at SAM modified gold electrodes Y1 - 2001 ER - TY - JOUR A1 - Scheller, Frieder W. A1 - Wollenberger, Ursula A1 - Warsinke, Axel A1 - Lisdat, Fred T1 - Research and development in biosensors Y1 - 2001 ER - TY - JOUR A1 - Rose, Andreas A1 - Pfeiffer, Dorothea A1 - Scheller, Frieder W. A1 - Wollenberger, Ursula T1 - Quinoprotein glucose dehydrogenasemodified thick-film electrodes for the amperometric detection of phenolic compounds in flow injection analysis Y1 - 2001 ER - TY - JOUR A1 - Sigolaeva, L. V. A1 - Markower, Alexander A1 - Eremenko, A. V. A1 - Makhaeva, G. F. A1 - Malygin, V. V. A1 - Kurochkin, I. N. A1 - Scheller, Frieder W. T1 - Bioelectrochemical anaysis of neuropathy targes esterase activity in blood Y1 - 2001 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 - Stöllner, Daniela A1 - Stöcklein, Walter F. M. A1 - Scheller, Frieder W. A1 - Warsinke, Axel T1 - Membrane-immobilized haptoglobin as affinity matrix for a hemoglobin-A1c-immunosensor Y1 - 2002 ER - TY - JOUR A1 - Scheller, Frieder W. T1 - Analytische Biochemie : Entwicklung von Biosensoren und Biochips Y1 - 2002 ER - TY - JOUR A1 - Scheller, Frieder W. A1 - Wollenberger, Ursula A1 - Lei, Chenghong A1 - Jin, Wen A1 - Ge, Bixia A1 - Lehmann, Claudia A1 - Lisdat, Fred A1 - Fridman, Vadim T1 - Bioelectrocatalysis by redox enzymes at modified electrodes Y1 - 2002 UR - www.elsevier.nl/inca/publications/6/0/1/3/4/7/index.htt ER - TY - JOUR A1 - Scheller, Frieder W. A1 - Bier, Frank Fabian T1 - Trends in der Bioanalytik Y1 - 2002 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 - Stoellner, Daniela A1 - Scheller, Frieder W. A1 - Warsinke, Axel T1 - Activation of cellulose membranes with 1,1ï-carbonyldiimidazole or 1-cyano-4-4-dimethylaminopyridinium tetrafluoroborate as a basis for the development of immunosensors Y1 - 2002 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 - Lei, Chenghong A1 - Wollenberger, Ursula A1 - Bistolas, Nikitas A1 - Guiseppi-Eli, A. A1 - Scheller, Frieder W. T1 - Electron transfer of hemoglobin at electrodes modified with colloidal clay nanoparticles Y1 - 2002 ER - TY - JOUR A1 - Ignatov, S. A1 - Shishniashvili, D. A1 - Ge, Bixia A1 - Scheller, Frieder W. A1 - Lisdat, Fred T1 - Amperometric biosensor based on a functionalized gold electrode for the detection of antioxidants Y1 - 2002 ER - TY - JOUR A1 - Scheller, Frieder W. A1 - Bauer, Christian G. A1 - Makower, Alexander A1 - Wollenberger, Ursula A1 - Warsinke, Axel A1 - Bier, Frank Fabian T1 - Immunoassays using enzymatic amplification electrodes Y1 - 2002 SN - 0-7484-0791-X ER - TY - JOUR A1 - Chen, Jian A1 - Stöcklein, Walter F. M. A1 - Scheller, Frieder W. A1 - Wollenberger, Ursula T1 - Electrochemical determination of human hemoglobin by using ferrocene carboxylic acid modified carbon powder microelectrode Y1 - 2003 ER - TY - JOUR A1 - Beissenhirtz, Moritz Karl A1 - Scheller, Frieder W. A1 - Lisdat, Fred T1 - Immobilized cytochrome c sensor in organic / aqueous media for the characterization of hydrophilic and hydrophobic antioxidants Y1 - 2003 ER - TY - JOUR A1 - Scheller, Frieder W. A1 - Wollenberger, Ursula T1 - Enzyme Electrodes Y1 - 2003 SN - 3-527-30401-0 ER - TY - JOUR A1 - Scheller, Frieder W. A1 - Bier, Frank Fabian T1 - Biosensoren Y1 - 2003 ER - TY - JOUR A1 - Scheller, Frieder W. A1 - Lettau, Kristian T1 - Biomimetische Rezeptoren und Biochips Y1 - 2003 ER - TY - JOUR A1 - Knösche, Kristina A1 - Halámek, Jan A1 - Makower, Alexander A1 - Fournier, Didier A1 - Scheller, Frieder W. T1 - Molecular recognition of cocaine by acetylcholinesterases for affinity purification and bio-sensing Y1 - 2003 ER - TY - JOUR A1 - Makower, Alexander A1 - Halámek, Jan A1 - Skládal, Petr A1 - Kernchen, Frank A1 - Scheller, Frieder W. T1 - New principle of direct real-time monitoring of the interaction of cholinesterase and its inhibitors by piezoelectric biosensor Y1 - 2003 ER - TY - JOUR A1 - Ehrentreich-Förster, Eva A1 - Scheller, Frieder W. A1 - Bier, Frank Fabian T1 - Detection of progesterone in whole blood samples N2 - The progesterone concentration in blood samples can be utilised as a marker for the diagnosis of early pregnancy, endocrinopathy and virilism. Here, we describe a method for progesterone detection and measurement in whole blood samples by a surface sensitive biosensor used in conjunction with an integrated optical grating coupler. This device determines refractive index changes near the biosensor's surface. Hence, biological species bound to a surface layer can be measured in real-time without any label. For the measurements, we have modified the indirect competitive immonoassay principle. The concentration of the progesterone antibody was kept at 1 µg/ml. Progesterone concentration was determined in buffer solution and whole blood in a range between 0.005 and 10 ng/ml. The detection limit was determined to be 3 pM. The relative standard deviation was calculated to be 3.5%. Y1 - 2003 ER - TY - JOUR A1 - Ge, Bixia A1 - Scheller, Frieder W. A1 - Lisdat, Fred T1 - Electrochemistry of immobilized CuZnSOD and FeSOD and their interaction with superoxide radicals N2 - Copper, zinc superoxide dismutase (CuZnSOD) from bovine erythrocytes and iron superoxide dismutase from Escherichia coli (FeSOD) were immobilized on 3-mercaptopropionic acid (MPA)-modified gold electrodes, respectively. The characterization of the SOD electrodes showed a quasi-reversible, electrochemical redox behavior with a formal potential of 47 ñ 4 mV and -154 ñ 5 mV (vs. Ag/AgCl, 1 M KCl) for surface adsorbed CuZnSOD and FeSOD, respectively. The heterogeneous electron transfer rate constants were determined to be about 65 and 35/s, respectively. Covalent fixation of both SODs was also feasible with only slight changes in the formal potential. The interaction of superoxide radicals (O2-) with the SOD electrode was investigated. No catalytic current could be observed. However, due to the fast cyclic reaction of SOD with superoxide, the communication of the protein with the electrode was strongly influenced. The amperometric detection of superoxide radicals is discussed. Y1 - 2003 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 - Pieper-Fürst, U. A1 - Kleuser, U. A1 - Stöcklein, Walter F. M. A1 - Warsinke, Axel A1 - Scheller, Frieder W. T1 - Detection of subicomolar concentrations of human matrix metalloproteinase-2 by an optical biosensor N2 - We describe in this paper the development of a one-step sandwich assay for the highly sensitive and fast detection of human matrix metalloproteinase (MMP)-2 (EC 3.4.24.24), using surface plasmon resonance (SPR). For the assay, two ligands were selected: monoclonal anti-MMP-2 antibody Ab-2 and the tissue inhibitor of metalloproteinases (TIMP)-2. They were chosen on the basis of (1) their affinities to MMP-2, (2) the efficiency of immobilization to the sensor chip, (3) the efficiency of adsorption to colloidal gold, and (4) the stability of these protein-coated gold particles. The assay included mixing of MMP-2 with antibody Ab-2 adsorbed to colloidal gold with a diameter of about 20 rim and injection into the flowcell of the SPR instrument containing immobilized TIMP-2. By using colloidal gold particles an amplification factor of 114 and a detection limit of 0.5 pM for MMP-2 were obtained. The precision of the assay was high even at low analyte concentrations, the standard deviation being 8.3% for five determinations of 1 pM MMP- 2. No significant binding was observed with the structurally related MMP-9. The assay is far more sensitive and faster than commonly used methods for MMP-2 detection. As TIMP-bound MMP-2 is not detected by this method, the assay can be applied for measuring free MMP-2, reflecting the imbalance of free and inhibitor-bound enzyme in various pathological situations. (C) 2004 Elsevier Inc. All rights reserved Y1 - 2004 ER - TY - JOUR A1 - Loew, Noya A1 - Scheller, Frieder W. A1 - Wollenberger, Ursula T1 - Characterization of self-assembling of glucose dehydrogenase in mono- and multilayers on gold electrodes N2 - Glucose dehydrogenase (GDH) was assembled electrostatically onto QCM-gold electrodes by their sequential deposition with anionic polyelectrolytes such as PSS and PASA. For the layer-by-layer arrangements both the microgravimetric and the electrochemical sensor signal were followed. Increasing amounts of GDH were deposited by stepwise formation of alternating layers of GDH and PSS or PASA. The mass increase was about 1.88 mug/cm(2) for one GDH/ PASA bilayer and 2.4 mug/cm(2) for a GDH/PSS bilayer. The addition of phenolic compounds resulted in an oxidation current, which could be catalytically increased by the GDH catalysed reaction in the presence of glucose. The system functions as glucose sensor when quinones are present in nonlimiting amount. The amperometric response was already diffusion limited when a single layer of GDH was adsorbed. The sensor sensitivity increased by a factor of 10 when MSA was used instead of MUA as initial electrode modifier Y1 - 2004 ER - TY - JOUR A1 - Lettau, Kristian A1 - Warsinke, Axel A1 - Laschewsky, André A1 - Mosbach, K. A1 - Yilmaz, E. A1 - Scheller, Frieder W. T1 - An esterolytic imprinted polymer prepared via a silica-supported transition state analogue N2 - In this work we describe a new preparation method for an esterolytic imprinted polymer with catalytic sites on the surface. A template was prepared by immobilizing a transition state analogue (phosphoramidic acid derivative) of an esterolytic reaction within porous silica particles. Polymerization within the pores was carried out using 4- vinylimidazole as a functional monomer and divinylbenzene as a cross-linker. The polymer was released by dissolution of the silica support with hydrofluoric acid and catalytic properties were studied by incubation with three different 4- nitrophenylesters and spectrophotometric determination of the released 4-nitrophenol. For 4-nitrophenyl acetate an activity of 211 nmol min(-1) mg(-1) and a K-m value of 2.2 mmol L-1 was obtained Y1 - 2004 ER - TY - JOUR A1 - Kulys, J. A1 - Krikstopaitis, K. A1 - Scheller, Frieder W. A1 - Wollenberger, Ursula T1 - Electrochemical parameters of phenoxazine derivatives in solution and at monolayer-modified gold electrodes N2 - Electrochemical properties of beta-(10-phenoxazinyl) propylamine (APPX) and beta-(10-phenoxazinyl) propionic acid (PPX) have been studied in solution, and in immobilized state on gold electrodes modified with monolayers of cystamine and mercaptoundecanoic acid. A reversible diffusion-controlled process of APPX and PPX was observed at a bare gold electrode. The electrochemical conversion of both compounds at modified gold electrodes was a quasireversible diffusion-controlled process. The redox potential of immobilized APPX (443 mV) was similar to the potential in solution, while the value of the immobilized PPX was 131 mV higher than in solution. The immobilized mediators were electrocatalytically active in the fungal peroxidase-catalyzed hydrogen peroxide reduction Y1 - 2004 ER - TY - JOUR A1 - Bistolas, Nikitas A1 - Christenson, A. A1 - Ruzgas, T. A1 - Jung, Christiane A1 - Scheller, Frieder W. A1 - Wollenberger, Ursula T1 - Spectroelectrochemistry of cytochrome P450cam N2 - The spectroelectrochemistry of camphor-bound cytochrome P450cam (P450cam) using gold electrodes is described. The electrodes were modified with either 4,4'-dithiodipyridin or sodium dithionite. Electrolysis of P450cam was carried out when the enzyme was in solution, while at the same time UV visible absorption spectra were recorded. Reversible oxidation and reduction could be observed with both 4,4'-dithiodipyridin and dithionite modified electrodes. A formal potential (E-0') of -373 mV vs Ag/AgCl 1 M KCl was determined. The spectra of P450cam complexed with either carbon monoxide or metyrapone, both being inhibitors of P450 catalysis, clearly indicated that the protein retained its native state in the electrochemical cell during electrolysis. (C) 2003 Elsevier Inc. All rights reserved Y1 - 2004 ER - TY - JOUR A1 - Beissenhirtz, Moritz Karl A1 - Scheller, Frieder W. A1 - Lisdat, Fred T1 - A superoxide sensor based on a multilayer cytochrome c electrode N2 - A novel multilayer cytochrome c electrode for the quantification of superoxide radical concentrations is introduced. The electrode consists of alternating layers of cytochrome c and poly(aniline(sulfonic acid)) on a gold wire electrode. The formation of multilayer structures was proven by SPR experiments. Assemblies with 2-15 protein layers showed electrochemical communication with the gold electrode. For every additional layer, a substantial increase in electrochemically active cytochrome c (cyt. c) was found. For electrodes of more than 10 layers, the increase was more than 1 order of magnitude as compared to monolayer electrode systems. Thermodynamic and kinetic parameters of the electrodes were characterized. The mechanism of electron transfer within the multilayer assembly was studied, with results suggesting a protein-protein electron-transfer model. Electrodes of 2-15 layers were applied to the in vitro quantification of enzymatically generated superoxide, showing superior sensitivity as compared to a monolayer-based sensor. An electrode with 6 cyt. c/PASA layers showed the highest sensitivity of the systems studied, giving an increase in sensitivity of half an order of magnitude versus the that of the monolayer electrode. The stability of the system was optimized using thermal treatment, resulting in no loss in sensor signal or protein loading after 10 successive measurements or 2 days of storage Y1 - 2004 SN - 0003-2700 ER - TY - JOUR A1 - Beissenhirtz, Moritz Karl A1 - Kwan, R. C. H. A1 - Ko, K. M. A1 - Renneberg, Reinhard A1 - Scheller, Frieder W. A1 - Lisdat, Fred T1 - Comparing in vitro electrochemical measurement of superoxide scavenging activity with an in vivo assessment of antioxidant potential in Chinese tonifying herbs N2 - The in vitro superoxide scavenging activity (as determined by electrochemical measurement) and the in vivo antioxidant potential (as determined by a mouse model of carbon tetrachloride (CCl4) hepatotoxicity) of methanolic extracts prepared from 10 Chinese tonifying herbs were compared. Electrochemical measurement using a cytochrome c (Cyt. c) sensor showed that all of the tested herbal extracts exhibited a medium superoxide scavenging activity of different potency, as indicated by their IC50 values. The in vivo measurement demonstrated that 80% of the herbal extracts displayed in vivo antioxidant potential, as assessed by the percentage of protection of the activity of plasma alanine aminotransferases and the hepatic glutathione regeneration capacity under CCl4-intoxicated condition. Although the in vitro antioxidant activity did not correlate quantitatively with the in vivo antioxidant potential, for 8 out of 10 samples a similar tendency was found. The rapid amperometric assessment of antioxidant potential by Cyt. c sensor may offer a convenient and direct method for screening as well as the quality control of herbal products. Copyright (C) 2004 John Wiley Sons, Ltd Y1 - 2004 ER - TY - JOUR A1 - Krylov, Andrey V. A1 - Beissenhirtz, Moritz Karl A1 - Adamzig, Holger A1 - Scheller, Frieder W. A1 - Lisdat, Fred T1 - Thick-film electrodes for measurement of superoxide and hydrogen peroxide based on direct protein-electrode contacts N2 - Cytochrome c was immobilized on screen-printed thick-film gold electrodes by a self-assembly approach using mixed monolayers of mercaptoundecanoic acid and mercaptoundecanol. Cyclic voltammetry revealed quasi-reversible electrochemical behavior of the covalently fixed protein with a formal potential of +10 mV vs. Ag/AgCl. Polarized at +150 mV vs. Ag/AgCl the electrode was found to be sensitive to superoxide radicals in the range 300-1200 nmol L-1. Compared with metal needle electrodes sensitivity and reproducibility could be improved and combined with the easiness of preparation. This allows the fabrication of disposable sensors for nanomolar superoxide concentrations. By changing the electrode potential the sensor can be switched from response to superoxide radicals to hydrogen peroxide-another reactive oxygen species. H2O2 sensitivity can be provided in the range 10-1000 mumol L-1 which makes the electrode suitable for oxidative stress studies Y1 - 2004 ER - TY - JOUR A1 - Scheller, Frieder W. A1 - Warsinke, Axel A1 - Pfeiffer, Dorothea A1 - Czeponik, J. T1 - Biosensorik / Bioanalytik Y1 - 2004 SN - 3-87081-372-5 ER - TY - JOUR A1 - Wollenberger, Ursula A1 - Bistolas, Nikitas A1 - Jung, Christiane A1 - Shumyantseva, V. V. A1 - Ruzgas, T. A1 - Scheller, Frieder W. T1 - Elektroden-Design für elektronische Wechselwirkung mit Monooxygenasen Y1 - 2004 SN - 3-8047-2132-x ER - TY - JOUR A1 - Kleuser, U. A1 - Stöcklein, Walter F. M. A1 - Pieper-Fürst, U. A1 - Scheller, Frieder W. T1 - Partikelverstärkte Oberflächenplasmonresonanz für die Quantifizierung von Matrix Metalloproteinase-2 Y1 - 2004 ER - TY - JOUR A1 - Scheller, Frieder W. A1 - Wagener, C. T1 - From gene to life Y1 - 2004 ER - TY - JOUR A1 - Scheller, Frieder W. A1 - Tiepner, K. A1 - Warsinke, Axel T1 - Anwendung von Biosensoren in der Lebensmittelanalytik Y1 - 2004 SN - 3-89947-120-2 ER - TY - JOUR A1 - Scheller, Frieder W. A1 - Bier, Frank Fabian T1 - Analytical Biochemistry (Editorial) Y1 - 2004 ER - TY - JOUR A1 - Lettau, Kristian A1 - Gajovic-Eichelmann, N. A1 - Kwak, Young-Keun A1 - Scheller, Frieder W. A1 - Warsinke, Axel T1 - Hydroxylasen und katalytische Polymere für Biochips Y1 - 2004 ER - TY - JOUR A1 - Beissenhirtz, Moritz Karl A1 - Scheller, Frieder W. A1 - Stöcklein, Walter F. M. A1 - Kurth, D. A1 - Möhwald, Helmuth A1 - Lisdat, Fred T1 - Electroactive cytochrome c multilayers within a polyelectrolyte assembly Y1 - 2004 ER - TY - JOUR A1 - Kröning, Steffen A1 - Scheller, Frieder W. A1 - Wollenberger, Ursula A1 - Lisdat, Fred T1 - Myoglobin-Clay Electrode for Nitric Oxide (NO) Detection in Solution Y1 - 2004 ER - TY - JOUR A1 - Mak, Wing Cheung A1 - Cheung, Kwan Yee A1 - Trau, Dieter A1 - Warsinke, Axel A1 - Scheller, Frieder W. A1 - Renneberg, Reinhard T1 - Electrochemical bioassay utilizing encapsulated electrochemical active microcrystal biolabels N2 - A new approach to perform electrochemical immunoassay based on the utilization of encapsulated microcrystal was developed. The microcrystal labels create a "supernova effect" upon exposure to a desired releasing agent. The microcrystal cores dissolve, and large amounts of signal-generating molecules diffuse across the capsule wall into the outer environment. Layer-by-Layer (LbL) technology was employed for the encapsulation of electrochemical signal- generating microcrystals (ferrocene microcrystals). The encapsulated microcrystals were conjugated with antibody molecules through the adsorption process. The biofunctionalized microcrystals were utilized as a probe for immunoassays. The microcrystal-based label system provided a high-signal molecule to antibody (SIP) ratio of 10(4)-10(5). Microcrystal biolabels with different antibody surface coverage (1.60-5.05 mg m(-2)) were subjected to a solid-phase immunoassay for the detection of mouse immunoglobulin G (M-IgG) molecules. The microcrystal-based immunoassay for the detection of M-IgG performed with microcrystals having antibody surface coverage of 5.05 mg m(-2) showed a sensitivity of 3.93 nA g(- 1) L-1 with a detection limit of 2.82 g L-1 Y1 - 2005 SN - 0003-2700 ER - TY - JOUR A1 - Liu, Songqin A1 - Wollenberger, Ursula A1 - Halamek, Jan A1 - Leupold, Eik A1 - Stöcklein, Walter F. M. A1 - Warsinke, Axel A1 - Scheller, Frieder W. T1 - Affinity interaction betwen phenylboronic acid-carrying self-assembled monolayers and FAD or HRP N2 - A method is provided for the recognition of glycated molecules based on their binding affinities to boronate- carrying monolayers. The affinity interaction of flavin adenine dinucleotide (FAD) and horseradish peroxidase (HRP) with phenylboronic acid monolayers on gold was investigated by using voltammetric and microgravimetric methods. Conjugates of 3-aminopherrylboronic acid and 3,3'-dithiodipropionic acid di(N-hydroxysuccinimide ester) or 11-mercaptoundecanoic acid were prepared and self-assembled on gold surfaces to generate monolayers. FAD is bound to this modified sur-face and recognized by a pair of redox peaks with a formal potential of -0.433 V in a 0.1 m phosphate buffer solution, pH 6.5. Upon addition of a sugar to the buffer, the bound FAD could be replaced, indicating that the binding is reversible. Voltammetric, mass measurements, and photometric activity assays show that the HRP can also be bound to the interface. This binding is reversible, and HRP can be replaced by sorbitol or removed in acidic solution. The effects of pH, incubation time, and concentration of H2O2 were studied by comparing the catalytic reduction of H2O2 in the presence of the electron-donor thionine. The catalytic current of the HRP-loaded electrode was proportional to HRP concentrations in the incubation solution in the range between 5 mu g mL(-1) and 0.4 mg mL(-1) with a linear slope of 3.34 mu A mL mg(-1) and a correlation coefficient of 0.9945 Y1 - 2005 ER - TY - JOUR A1 - Halamek, Jan A1 - Makower, Alexander A1 - Knösche, Kristina A1 - Skladal, Petr A1 - Scheller, Frieder W. T1 - Piezoelectric affinity sensors for cocaine and cholinesterase inhibitors N2 - We report here the development of piezoelectric affinity sensors for cocaine and cholinesterase inhibitors based on the formation of affinity complexes between an immobilized cocaine derivative and an anti-cocaine antibody or cholinesterase. For both binding reactions benzoylecgonine-1,8-diamino-3,4-dioxaoctane (BZE-DADOO) was immobilized on the surface of the sensor. For immobilization. pre-conjugated BZE-DADOO with 11-mercaptomonoundecanoic acid (MUA) via 2- (5-norbornen-2,3-dicarboximide)-1,1,3,3-tetramethyluronium-tetrafluoro borate (TNTU) allowed the formation of a chemisorbed monolayer on the piezosensor surface. The detection of cocaine was based oil a competitive assay. The change of frequency measured after 300 s of the binding reaction was used as the signal. The maximum binding of the antibody resulted in a frequency decrease of 35 Hz (with an imprecision 3%, n = 3) while the presence of 100 pmol I-1 cocaine decreased the binding by 11%. The limit of detection was consequently below 100 pmol I-1 for cocaine. The total time of one analysis was 15 min. This BZE-DADOO-modified sensor was adapted for the detection of organophosphates. BZE-DADOO - a competitive inhibitor - served as binding element for cholinesterase in a competitive assay. (C) 2004 Elsevier B.V. All rights reserved Y1 - 2005 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 - TY - JOUR A1 - Scheller, Frieder W. A1 - Bistolas, Nikitas A1 - Liu, Songqin A1 - Jänchen, Michael A1 - Katterle, Martin A1 - Wollenberger, Ursula T1 - Thirty years of haemoglobin electrochemistry N2 - Electrochemical investigations of the blood oxygen carrier protein include both mediated and direct electron transfer. The reaction of haemoglobin (Hb) with typical mediators, e.g., ferricyanide, can be quantified by measuring the produced ferrocyanide which is equivalent to the Hb concentration. Immobilization of the mediator within the electrode body allows reagentless electrochemical measuring of Hb. On the other hand, entrapment of the protein within layers of polyclectrolytes, lipids, nanoparticles of clay or gold leads to a fast heterogeneous electron exchange of the partially denatured Hb. (c) 2005 Elsevier B.V. All rights reserved Y1 - 2005 ER - TY - JOUR A1 - Scheller, Frieder W. A1 - Lisdat, Fred A1 - Wollenberger, Ursula T1 - Application of electrically contacted enzymes for biosensors Y1 - 2005 SN - 3-527- 30690-0 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 - Teller, C. A1 - Halamek, Jan A1 - Makower, Alexander A1 - Fournier, Didier A1 - Schulze, H. A1 - Scheller, Frieder W. T1 - A piezoelectric sensor with propidium as a recognition element for cholinesterases N2 - A piezoelectric biosensor has been developed on the basis of the reversible acetylcholinesterase (AChE) inhibitor propidium. The propidium cation was bound to a 11-mercaptoundecanoic acid monolayer on gold-coated quartz crystals. The immobilization was done via activation of carboxyl groups by 1,3-dicyclohexylcarbodiimide (DCC). Different types of cholinesterases (acetyl- and butyryl-ChE) from different origins were tested for their binding ability towards the immobilized propidium. Binding Studies were performed in a flow system, Furthermore, catalytically active and organophosphate-inhibited enzyme were compared re-aiding their binding capability. The binding constants were derived by using an one to one binding model and a refined model also including rebinding effects. It was shown that organophosphorylation of the active site hardly influences the affinity of AChE towards propidium. Furthermore the propidium-based biosensor provides equal sensitivity as compared with piezolelectric sensors with immobilized paraoxon- an active site ligand of AChE. (c) 2005 Elsevier B.V. All rights reserved Y1 - 2006 U6 - https://doi.org/10.1016/j.snb.2005.02.053 ER - TY - JOUR A1 - Halamek, Jan A1 - Teller, Carsten A1 - Zeravik, Jiri A1 - Fournier, Didier A1 - Makower, Alexander A1 - Scheller, Frieder W. T1 - Characterization of binding of cholinesterases to surface immobilized ligands N2 - We summarize here the development of various piezoelectric biosensors utilizing cholinesterase (ChE) as the recognition element. In our work we studied the interaction between cholinesterase and its ligands (propidium, carnitine, benzylgonine-1,8-diamino-3,4-dioxaoctane (BZE-DADOO) and paraoxon). The sensor modification was based on a self-assembled monolayer (SAM) of a thiol compound (11-mercaptoundecanoic acid) on the gold electrode and the subsequent covalent coupling of the cholinesterase ligand to this SAM. The ligand-modified piezoelectric sensors were placed in a flow system to allow the on-line monitoring of cholinesterase binding and the enzymatic activity quantification by amperometry. Cholinesterases from different species-acetylcholinesterase (AChE) from Electrophorus electricus , AChE from Drosophila melanogaster , and butyrylcholinesterase (BChE) of human origin-were tested on the various immobilized ligands. Our research allowed the development of a competitive assay for the detection of organophosphates in river water samples using the BZE-DADOO-modified piezosensor. Another direction of research was pointed on the characterization of the interactions between ChE and its ligands. The kinetic binding constants were derived using a one- to-one binding model Y1 - 2006 UR - http://www.informaworld.com/openurl?genre=journal&issn=0003-2719 U6 - https://doi.org/10.1080/00032710600713107 SN - 0003-2719 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 - 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 - 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 - 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 -