Disposable, micro-fluidic biosensor array for online analysis of adherent cells activity combining Quartz Crystal Resonators and Impedance measurement techniques

Autor :Gianluca Cama
Herkunft :OvGU Magdeburg, Fakultät für Elektrotechnik und Informationstechnik
Datum :08.03.2011
Dokumente :
Dataobject from HALCoRe_document_00010363
Typ :Dissertation
Format :Text
Kurzfassung :In the present work, a novel micro-fluidic biosensor array for fast online adherent cell monolayer (e.g. living epithelial cells) analysis during cell proliferation and stimulation was developed. The new device combines 16 quartz crystal resonators and 16 impedimetric sensors to acquire complementary sets of measurement data, namely the acoustic shear response and the transepithelial impedance of the cell layer. Sensor responses are analysed by means of impedance spectroscopy in the MHz range. Time-lapse light microscopy through transparent microelectrodes was employed for visual characterisation of the cell monolayers. To allow parallelized cell cultivation the new biosensor array consists of 4 bioreactor units and a flow distribution network embedded within the same device. Each bioreactor unit houses 4 quartz crystal resonators and 4 impedimetric sensors for the simultaneous analysis of four cell populations. In order to achieve the parallel cultivation of different cell populations the flow distribution network was designed with symmetric structure. This enables the equal partitioning of the cell suspension and the media providing the same initial cell concentration and identical conditions during cell growth and stimulation among all the cell populations cultivated within the biosensor array. Moreover, the array was designed to be operated in flow-through and overpressure regime. An external flow injection system provides automated and parallelized media feed as well as the control of the overpressure regime. This approach enables well defined proliferation and stimulation conditions. Besides, it prevents the accumulation of contaminants. Injection molding technology was chosen for the cheap mass production of the microfluidic array so that disposable parts made of biocompatible polymer could be fabricated. Thin-film deposition techniques were applied for the sensors fabrication. New dedicated sensor interface electronics including a multiplexer for all the 32 sensors were developed to allow fast and parallelized spectra acquisition with a miniaturized impedance analyser. To prove the assumption of equal flow circulation within the symmetric micro-channel network and support the hypothesis of identical cultivation conditions for the cells living above the sensors, the influence of fabrication tolerances on the flow regime has been simulated. As well, the shear stress on the adherent cell layer due to the flowing media was characterized. Furthermore, the injection molding process was simulated in order to optimize the mold geometry and minimize the shrinkage and the warpage of the parts as well as to ensure an even resident time of the melt in the mold. Madin-Darby Canine Kidney cells were cultivated in the biosensor array. During experiments, the cell behaviour during cell proliferation and stimulation was analyzed online. It is believed that in the future, the new biosensor array can be successfully employed as a tool supporting standard techniques employed in molecular cell biology for the study of that complex system of communication that governs basic cellular activities and coordinates cell actions.
Schlagwörter :akustische Biosensoren, Mikrofluidik, Spritzgusstechnologie, Zelladhäsion, Biosensor-Array, Impedanzspektroskopie
Rechte :Dieser Text ist urheberrechtlich geschützt
Größe :X, 98 S.
Erstellt am :28.03.2011 - 12:36:19
Letzte Änderung :28.03.2011 - 12:39:03
MyCoRe ID :HALCoRe_document_00010363
Statische URL :http://edoc.bibliothek.uni-halle.de/servlets/DocumentServlet?id=10363