Date

2015

Document Type

Dissertation

Degree

Doctor of Philosophy

Department

Electrical Engineering

First Adviser

Hwang, James C. M.

Other advisers/committee members

Hatalis, Miltiadis K.; Tatic-Lucic, Svetlana; Cheng, Xuanhong; Palego, Cristiano

Abstract

Unlike traditional methods of cell detection which accomplished through chemical or optical means, electrical cell detection can be label-free and nondestructive with high throughput. Broadband electrical detection can have additional advantages. For example, based on the different dispersion characteristics, live and dead cells can be differentiated at MHz frequencies, cell types can be identified at GHz frequencies, and surface functionality can be detected at THz frequencies.To resolve the dilemma encountered by Coulter counters and to evolve a general-purpose electrical detection technique, broadband microwave measurement is used to overcome electrode polarization, AC dielectrophoresis to precisely place cells between narrowly spaced electrodes for maximum cell-to-sample volume ratio, and relatively wide microfluidic channels to prevent cell clogging. This thesis work mainly presents detailed data and analysis at higher frequencies (GHz vs. MHz) to prove that the unique combination of these approaches can be reproducibly sensitive to single cells of different types. The electric circuit model that generated from different electrode designs of CPW and CPS consistently extracts the same value for the resistance of the cytoplasm. Furthermore, simple analysis of the data confirms that microwave signals can penetrate through the cell membrane to probe the properties of cytoplasm.

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