title: Miniaturized thin film glutamate and glutamine biosensors.
abstract: Integrated thin film biosensors were developed for the simultaneous measurement of L-glutamine and L-glutamate in a mu-flow cell. Due to a novel glutaminase with an activity optimum in the neutral pH range, direct monitoring of glutamine in a mammalian cell culture medium could be performed. The glutamine bienzyme sensor was prepared by co-immobilization of glutaminase with glutamate oxidase within a photopatterned poly(2-hydroxyethyl methacrylate) (pHEMA) hydrogel membrane. The sensor response was linear in the concentration range of 50 mumol to 10 mmol glutamine/l. Additionally, a glutamate biosensor was integrated on the sensor chip for difference measurement of possible glutamate interferences. The sensor-chip could be used for at least 300 measurements without any alteration in the performance of its sensors. A new sensor-chip with an integrated flow cell provided the possibility of simultaneous measurement of four different parameters at a cell volume of 1 microliter. In order to complete the microsystem, and in order to obtain a "lab on chip", a battery operated surface mounted device (SMD) potentiostat was developed.
authors.affiliation: Technical University of Vienna, Institute for Biomedical Microtechniques and Sensorics, Austria.
authors.forename: I
authors.initials: I
authors.lastname: Moser
authors.forename: G
authors.initials: G
authors.lastname: Jobst
authors.forename: E
authors.initials: E
authors.lastname: Aschauer
authors.forename: P
authors.initials: P
authors.lastname: Svasek
authors.forename: M
authors.initials: M
authors.lastname: Varahram
authors.forename: G
authors.initials: G
authors.lastname: Urban
authors.forename: V A
authors.initials: VA
authors.lastname: Zanin
authors.forename: G Y
authors.initials: GY
authors.lastname: Tjoutrina
authors.forename: A V
authors.initials: AV
authors.lastname: Zharikova
authors.forename: T T
authors.initials: TT
authors.lastname: Berezov
mesh_terms: D015374:Biosensing Techniques; D002138:Calibration; D018698:Glutamic Acid / Q000032:analysis*; D005973:Glutamine / Q000032:analysis*; D006863:Hydrogen-Ion Concentration
chemical_list: D005973:Glutamine; D018698:Glutamic Acid