Date

5-1-2018

Document Type

Thesis

Degree

Master of Science

Department

Electrical and Computer Engineering

First Adviser

Hwang, James C.

Abstract

For the first time, single-cell trapping, characterization, electroporation, and de-trapping were demonstrated by conveniently programming the frequency and power of the same ultra-wideband vector network analyzer (VNA) to perform the different functions across its bandwidth of 9 kHz‒9 GHz. On one hand, trapping of a live biological cell was accomplished by applying to a coplanar waveguide (CPW) through the VNA a continuous wave (CW) signal of 3 dBm and 5 MHz, corresponding to attractive dielectrophoresis. On the other hand, detrapping of a live biological cell was also accomplished to complete a better control of the cell in microfluidics using electromagnetic method, after both the lower and the higher crossover frequencies of Clausius-Mossotti function were carefully studied. A detrapping experiment was designed to validate the CM function, which demonstrated that the lower and the higher crossover frequencies were around 60 kHz and 300 MHz, respectively, from positive force to negative force in single-cell dielectrophoresis predicted by the Clausius-Mossotti function theoretical calculation, despite the highly nonuniform electric field distribution between small and narrowly spaced electrodes, which was greatly disturbed by the cell. The validation was based on live Jurkat human T-lymphocyte cells that were resuspended in isotonic sucrose solution, and should be further tested on different cells in their culture media. With further validation, the Clausius-Mossotti function can be used to help optimize the dielectrophoresis configuration and algorithm for more complicated cell manipulation. After a cell is trapped on the CPW, the VNA was switched to 9 dBm and 100 kHz for electroporation. Before and after electroporation, the cell could be characterized from 9 kHz to 9 GHz by setting the VNA at −18 dBm to assess the effect of electroporation. This breakthrough not only greatly improves the accuracy and efficiency of electrical cell characterization, but also can enable its throughput to approach that of optical cytometers in the future.

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