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Redox Hydrogel‐Based Bienzyme Microelectrodes for Amperometric Monitoring of L ‐Glutamate
Author(s) -
Mikeladze Ekaterina,
Schulte Albert,
Mosbach Marcus,
Blöchl Andrea,
Csöregi Elisabeth,
Solomonia Revaz,
Schuhmann Wolfgang
Publication year - 2002
Publication title -
electroanalysis
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.574
H-Index - 128
eISSN - 1521-4109
pISSN - 1040-0397
DOI - 10.1002/1521-4109(200203)14:6<393::aid-elan393>3.0.co;2-p
Subject(s) - amperometry , microelectrode , glutamate receptor , horseradish peroxidase , biosensor , chemistry , redox , biophysics , electrode , electrochemistry , biochemistry , inorganic chemistry , biology , receptor , enzyme
Fabrication and characterization of amperometric bienzyme L ‐glutamate sensitive microelectrodes are the prerequisite for monitoring changes of L ‐glutamate concentration at glutamate‐secreting cell cultures. The design of the glutamate microelectrodes is based on incorporating L ‐glutamate oxidase and horseradish peroxidase into a redox‐hydrogel containing PVI 19 ‐dmeOs as the redox mediator and immobilizing this system onto the surface of platinum microdisk electrodes using a dip‐coating procedure. For amperometric measurements of L ‐glutamate, these redox hydrogel‐based bienzyme microelectrodes can be operated at low working potentials (−50 mV vs. Ag/AgCl) decreasing the influence of electroactive interferants possibly present in biological samples. The L ‐glutamate microsensors are characterized by a good operation stability and sensitivity (0.038±0.005 mA M −1 ), a low detection limit (0.5 μM in a conventional amperometric set‐up and 0.03 μM in a Faraday cage, defined as three times the signal‐to‐noise ratio), a linear range up to 50 μM and a response time of about 35 s. The glutamate biosensors have been applied for the direct measurement of L ‐glutamate release (upon chemical stimulation) from a population of immortalized hippocampal neurons (HN10 cells) demonstrating the possibility to amperometrically monitor in‐situ L ‐glutamate secretion from these cells.