@article{HalamekTellerZeraviketal.2006,
  author    = {Halamek, Jan and Teller, Carsten and Zeravik, Jiri and Fournier, Didier and Makower, Alexander and Scheller, Frieder W.},
  title     = {Characterization of binding of cholinesterases to surface immobilized ligands},
  issn      = {0003-2719},
  doi       = {10.1080/00032710600713107},
  year      = {2006},
  abstract  = {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},
  language  = {en}
}
@article{HalamekTellerMakoweretal.2006,
  author    = {Halamek, Jan and Teller, Carsten and Makower, Alexander and Fournier, Didier and Scheller, Frieder W.},
  title     = {EQCN-based cholinesterase biosensors},
  issn      = {0013-4686},
  doi       = {10.1016/j.electacta.2006.03.047},
  year      = {2006},
  abstract  = {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.},
  language  = {en}
}
@article{BeissenhirtzSchellerViezzolietal.2006,
  author    = {Beissenhirtz, Moritz Karl and Scheller, Frieder W. and Viezzoli, Maria Silvia and Lisdat, Fred},
  title     = {Engineered superoxide dismutase monomers for superoxide biosensor applications},
  issn      = {0003-2700},
  doi       = {10.1021/Ac051465g},
  year      = {2006},
  abstract  = {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},
  language  = {en}
}
@article{LiuWollenbergerKatterleetal.2006,
  author    = {Liu, Songqin and Wollenberger, Ursula and Katterle, Martin and Scheller, Frieder W.},
  title     = {Ferroceneboronic acid-based amperometric biosensor for glycated hemoglobin},
  issn      = {0925-4005},
  doi       = {10.1016/j.snb.2005.07.011},
  year      = {2006},
  abstract  = {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.},
  language  = {en}
}
@article{NitscheKurthDunkhorstetal.2007,
  author    = {Nitsche, Andreas and Kurth, Andreas and Dunkhorst, Anna and P{\"a}nke, Oliver and Sielaff, Hendrik and Junge, Wolfgang and Muth, Doreen and Scheller, Frieder W. and St{\"o}cklein, Walter F. M. and Pauli, Georg and Kage, Andreas},
  title     = {One-step selection of vaccinia virus binding DNA-aptamers by MonoLEX},
  doi       = {10.1186/1472-6750-7-48},
  year      = {2007},
  language  = {en}
}
@article{KappBeissenhirtzGeyeretal.2006,
  author    = {Kapp, Andreas and Beissenhirtz, Moritz Karl and Geyer, F. and Scheller, Frieder W. and Viezzoli, Maria Silvia and Lisdat, Fred},
  title     = {Electrochemical and sensorial behaviour of SOD mutants immobilized on gold electrodes in aqueous / organic solvent mixtures},
  issn      = {1040-0397},
  doi       = {10.1002/elan.200603620},
  year      = {2006},
  language  = {en}
}