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Michel M.A. Francois
Advisors: Kambiz Pourrezaei, Ph.D. and Ryszard Lec, Ph.D.
Abstract:
Demands exist for rapid, sensitive, selective and portable biosensors for monitoring a variety of biochemical and biological processes in medicine, pharmaceutical, health care and a variety of environmental conditions. Attractive and promising solutions to these needs are emerging as concepts of a low cost and easy to use analytical system such as a BioChemLab-on-chip (Biochip). These types of devices represent a large-scale integration of various biological, mechanical, and electrical functionalized components and require the integration of transducers (optical, acoustic, others), sensing interfaces (biofunctionalized surfaces), sample delivery (microfluidic), and signal processing and control (electronics) on a single substrate. The major challenges in making these devices are mostly related to 3-D design structures and the development of novel fabrication processes that need to address a complex bio-electronic working environment. This thesis is focused on the development and testing of processes and performance of a Biochip based on piezoelectric thickness shear mode (TSM) sensing technology.
The device consists of an array of acousto-electronic (piezoelectric/electrostrictive) sensors fabricated on a single electroacoustic (piezoelectric/electrostrictive) quartz wafer or substrate. A micro-fluidic line is constructed on the same substrate to deliver the measurands on the electrodes of the different frequency sensors. Three different processes to fabricate this multi-frequency biochip are detailed in this work. The biochip is designed in a way that allows us to do studies on how to improve the design rules and better fabricate this type of devices in the future. The multi-sensor device is applicable to both gaseous and liquid phase measurements. We demonstrate the application of this device to measure different measurands simultaneously under a broad range of experimental conditions. Experimental studies have shown several interesting features of piezo-arrays, for example, by decreasing their electrode diameter by 25%, their ?ƒ increases by 47%. We developed a new design structure (clustering small electrodes and shorting them together) to improve the amplitude response, as well as increase the sensitivity and dynamic range of the AEBSA. We also developed new design criteria that allow further shrinkage of the biochip. The obtained results provide a foundation for the development of a fully integrated piezo-biochip.
Friday, April 13th, 2007 at 10 a.m.
MEM Seminar Room, Curtis 162
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