Impedance spectroscopy as a non-destructive in-process control approach for neurochip fabrication / von Isabella Schmied
Verfasser / Verfasserin Schmied, Isabella
Begutachter / BegutachterinBertagnolli, Emmerich ; Wanzenböck, Heinz
ErschienenWien, 2017
Umfang79 Blätter : Illustrationen, Diagramme
HochschulschriftTechnische Universität Wien, Diplomarbeit, 2017
Zusammenfassung in deutscher Sprache
Schlagwörter (DE)Impedanz Analyse
Schlagwörter (EN)impedance-analyis / neurochip fabrication
URNurn:nbn:at:at-ubtuw:1-99189 Persistent Identifier (URN)
 Das Werk ist frei verfügbar
Impedance spectroscopy as a non-destructive in-process control approach for neurochip fabrication [6.03 mb]
Zusammenfassung (Englisch)

Microelectrode arrays (MEAs) have a wide field of application in chemical, biological and pharmaceutical research. Starting from in-vitro tests of cell cultures for preclinical testing, like cell-drug interactions, to in-vivo response tests. For biological in-vitro electrophoresis, MEAs are especially popular due to their large number of measuring electrodes and the low amount of required measurement media. Typically, the flow of liquid media is controlled by channel structures. Those are embedded in an attachment block, which is mounted on top of the MEA. This work focus on a transepithelial measurement setup for detecting impedance differences. By using electrical impedance spectroscopy (EIS), different variations can be detected. For basic evaluations, the measurement and comparison of each microelectrode on a MEA is used to dedicate defects and inaccuracies originated from the fabrication process.^ Through comparison of different measurements, the electrical properties of the different media depending on the frequency can be detected. Thereby, the physiological change yields to changes in the measured impedance. Another approach is the detection of a biological layer on the electrodes, like an overall protein layer or an isolated attachment of cells. First, the performance of the whole setup was tested. Therefore, the sensitivity and frequency dependency of the microelectrodes were measured on a wide frequency range. To evaluate the dataset statistically and detect possible outliers, the distribution was analyzed in detail. Another part was the detection of repeatability of the measurement data. To improve the performance of the setup, different properties were analyzed. First, a new transepithelial setup was fabricated and evaluated by comparison with the former setup.^ Another approach was the evaluation of the influence of different deposition methods of electrode material on the morphology of the layers and the measured impedance values. In the next step, properties concerning the microelectrodes were varied and the resulting measurement values were discussed in detail. Starting from the choice of biomaterial, the variation of electrode thickness to the variation of microelectrode size. Another evaluation discussed the structure of the MEA, concerning different lengths of connecting leads between microelectrodes and outer contact electrodes. Finally, the suitability of the measurement setup for detection of different biological media was tested. The analysis started at different cell media with and without serum and compared the results with former measured Ringer¿s solution. In the next part, the influence of a protein coating layer on the measurement results was shown.^ The last part concerns the suitability of measuring cell attachment of PC-12 cells.

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