Date of Award

2015

Document Type

Master's Thesis

Degree Name

Master of Science in Electrical Engineering (MS)

College, School or Department Name

Department of Electrical and Computer Engineering

Advisor

Paul L. Bergstrom

Abstract

There is need to develop a fast and efficient procedure for detecting blood type that makes use of an electronic measurement to minimize human error and is portable so that it can be used in triage situations. A process to develop a crossover frequency based blood typing device is described. Alternating field drives red blood cells over the sensing electrodes and depending on the capacitance measured between pairs of sensing electrodes, the position of these RBCs can be determined. The convergence/divergence of these cells at a particular frequency determines blood type, since each type has a characteristic frequency. This project aims to obviate the need for optics in blood typing by making use of a purely electric measurement.

A microdevice was fabricated with different designs of sensing electrodes. These electrodes were passivated using Parylene-C and hafnia. A fluidic chamber was placed over them, with inlet/outlet ports for RBCs suspended in solution. An LCR meter was used to measure capacitance between different pairs of electrodes. While testing is still in progress, preliminary data suggests measurable difference in capacitance between readings taken when the fluidic chamber was filled with just ultrapure water, phosphate buffered solution and solution containing RBCs, proving this method as a viable route to blood typing.

Analytical calculations and COMSOL 4.4 simulations suggest coupling of sensing frequency to the driving frequency will necessitate switching in order to improve accuracy. Areas of high cell concentration were studied and these will be used for optimizing design of sensing electrodes to improve accuracy.

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