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 - 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 - 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 - 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 - 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 - CHAP A1 - Asche, Hartmut A1 - Böckmann, Christine A1 - Laue, Steffen A1 - Löhmannsröben, Hans-Gerd A1 - Lemke, Matthias A1 - Schober, Lars A1 - Reich, Oliver A1 - Lück, Erika A1 - Schütte, Marc A1 - Domsch, Horst A1 - Makower, Alexander A1 - Scheller, Frieder W. A1 - Stöcklein, Wolfgang A1 - Wollenberger, Ursula A1 - Schultze, Rainer A1 - Hengstermann, Theo A1 - Schael, Frank T1 - Umweltforschung für das Land Brandenburg : Projekt Umweltanalytik / Umweltmeßtechnik / Informationssysteme Y1 - 2000 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus-3862 SP - 176 EP - 227 ER - TY - JOUR A1 - Eremenko, A. V. A1 - Makower, Alexander A1 - Bauer, Christian G. A1 - Kurochkin, I. N. A1 - Scheller, Frieder W. T1 - A bienzyme electrode for tyrosine containing peptides determination Y1 - 1997 ER - TY - JOUR A1 - Szeponik, Jan A1 - Möller, B. A1 - Pfeiffer, Dorothea A1 - Lisdat, Fred A1 - Wollenberger, Ursula A1 - Makower, Alexander A1 - Scheller, Frieder W. T1 - Ultrasensitive bienzyme sensor for adrenaline Y1 - 1997 ER - TY - JOUR A1 - Makower, Alexander A1 - Eremenko, A. V. A1 - Streffer, Katrin A1 - Wollenberger, Ursula A1 - Scheller, Frieder W. T1 - Tyrosinase-glucose dehydrogenase substrate-recycling biosensor : a highly sensitive measurement of phenolic compounds Y1 - 1996 ER -