title: In situ monitoring of myenteric neuron activity using acetylcholinesterase-modified AlGaN/GaN solution-gate field-effect transistors.
abstract: The response characteristics of acetylcholinesterase-modified AlGaN/GaN solution-gate field-effect transistors (AcFETs) are quantitatively analyzed by means of a kinetic model. The characterization shows that the covalent enzyme immobilization process yields reproducible AcFET characteristics with a Michaelis constant KM of (122 ± 4) μM for the immobilized enzyme layer. The increase of KM by a factor of 2.4 during the first four measurement cycles is attributed to partial denaturation of the enzyme. The AcFETs were used to record the release of acetylcholine (ACh) by neuronal tissue cultivated on the gate area upon stimulation by rising the extracellular K(+) concentration. The neuronal tissue constituted of isolated myenteric neurons from four to 12 days old Wistar rats, or sections from the muscularis propria containing the myenteric plexus from adult rats. For both cases the AcFET response was demonstrated to be related to the activity of the immobilized acetylcholinesterase using the reversible acetylcholinesterase blocker donepezil. A concentration response curve of this blocking agent revealed a half maximal inhibitory concentration of 40 nM which is comparable to values measured by complementary in vitro methods.
authors.affiliation: I. Physikalisches Institut, Justus-Liebig-Universität Gießen, Heinrich-Buff-Ring 16, 35392 Gießen, Germany. Electronic address: gesche.m.muentze@exp1.physik.uni-giessen.de.
authors.forename: Gesche Mareike
authors.initials: GM
authors.lastname: Müntze
authors.affiliation: Institut für Veterinär-Physiologie und -Biochemie, Justus-Liebig-Universität Gießen, Frankfurter Straße 100, 35392 Gießen, Germany.
authors.forename: Ervice
authors.initials: E
authors.lastname: Pouokam
authors.affiliation: Institut für Veterinär-Physiologie und -Biochemie, Justus-Liebig-Universität Gießen, Frankfurter Straße 100, 35392 Gießen, Germany.
authors.forename: Julia
authors.initials: J
authors.lastname: Steidle
authors.affiliation: I. Physikalisches Institut, Justus-Liebig-Universität Gießen, Heinrich-Buff-Ring 16, 35392 Gießen, Germany.
authors.forename: Wladimir
authors.initials: W
authors.lastname: Schäfer
authors.affiliation: I. Physikalisches Institut, Justus-Liebig-Universität Gießen, Heinrich-Buff-Ring 16, 35392 Gießen, Germany.
authors.forename: Alexander
authors.initials: A
authors.lastname: Sasse
authors.affiliation: I. Physikalisches Institut, Justus-Liebig-Universität Gießen, Heinrich-Buff-Ring 16, 35392 Gießen, Germany.
authors.forename: Kai
authors.initials: K
authors.lastname: Röth
authors.affiliation: Institut für Veterinär-Physiologie und -Biochemie, Justus-Liebig-Universität Gießen, Frankfurter Straße 100, 35392 Gießen, Germany.
authors.forename: Martin
authors.initials: M
authors.lastname: Diener
authors.affiliation: I. Physikalisches Institut, Justus-Liebig-Universität Gießen, Heinrich-Buff-Ring 16, 35392 Gießen, Germany.
authors.forename: Martin
authors.initials: M
authors.lastname: Eickhoff
mesh_terms: D000110:Acetylcholinesterase / Q000737:chemistry / Q000378:metabolism*; D017607:Aluminum Compounds / Q000737:chemistry*; D000818:Animals; D015374:Biosensing Techniques; D002478:Cells, Cultured; D017076:Computer-Aided Design; D003217:Conductometry / Q000295:instrumentation*; D004789:Enzyme Activation; D004800:Enzymes, Immobilized; D004867:Equipment Design; D019544:Equipment Failure Analysis; D005708:Gallium / Q000737:chemistry*; D008991:Monitoring, Physiologic / Q000295:instrumentation; D009197:Myenteric Plexus / Q000166:cytology / Q000378:metabolism*; D009474:Neurons / Q000201:enzymology*; D051381:Rats; D017208:Rats, Wistar; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D014173:Transistors, Electronic
chemical_list: D017607:Aluminum Compounds; D004800:Enzymes, Immobilized; C513700:aluminum gallium nitride; C038863:gallium oxide; C052045:aluminum nitride; D005708:Gallium; D000110:Acetylcholinesterase
keywords: Acetylcholineseterase; AlGaN/GaN HEMT; Bioelectronics; Cell-transistor hybrid; EnFET; Neuron activity