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 - Ehrentreich-Förster, Eva A1 - Scheller, Frieder W. T1 - Charakterisierung antioxidativer Substanzen mit einem Superoxidsensor Y1 - 1997 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 - 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 - 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 - 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 - 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 - 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 - Markower, Alexander A1 - Wollenberger, Ursula A1 - Hörtnagel, H. A1 - Pfeiffer, Dorothea A1 - Scheller, Frieder W. T1 - Catecholamine detection using enzymatic amplification Y1 - 1997 ER -