Date of Award

12-2015

Document Type

Thesis

Degree Name

Master of Science (MS)

Legacy Department

Electrical Engineering

Advisor

Wang, Pingshan

Committee Member

Harrell, William R

Committee Member

Koley, Goutam

Abstract

This thesis presents a series of studies on single particle and biological cell detection and differentiation by a radio frequency (RF) interferometer system. Several techniques, such as dielectrophoresis (DEP), time domain method and 3D focusing have been illustrated and investigated to demonstrate the capacity of interrogating the electric property of single particle or biological cell by the RF interferometer. Silica particles and live yeast cells are trapped at the sensing area by DEP force and detected by the RF sensor. Solutions of particle mixtures (~4 μm silica and ~10 μm polystyrene) and cell mixtures (viable and non-viable yeast cells, normal and cancer human breast cells, healthy and malaria infected red blood cells) are infused into a microfluidic channel, separately, and measured at ~ 3 GHz in time domain, indicating that individual particles and cells can be effectively detected and differentiated. RF measurement of silica particles, normal and cancer human breast cells, healthy and malaria infected red blood cells is also conducted at multiple frequency points due to the tunability of the RF interferometer system. The results show that higher working frequency provides higher sensitivity of detecting and differentiating single particles and cells. Theoretical analysis and simulation is beneficial to elucidate and verify the measurement results. Moreover, 3D focusing technique and low cost RF sensor design is proposed in order to better control the trace of particles and cells travelling through the microfluidic channel, and meanwhile, eliminate position affects on RF signal response induced by individual particle or cell. Future work is needed to precisely control cell positions, characterize the cells at more frequency points, and obtain quantified cell properties.

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