Abstract

Capillary electrophoresis laser-induced fluorescence (CE-LIF) is widely used to detect both the presence and concentration of fluorescently labeled biomolecules. In CE-LIF, a plug of sample fluid is electrophoretically driven down a microchannel using a high voltage applied between the opposite ends of the microchannel. Molecules of different sizes and charge states travel at different velocities down the channel. Laser light with a wavelength in the excitation band of the fluorophores is focused near the end of the channel. As each species of molecule passes through the laser spot, the fluorophores emit a fluorescence signal which is measured with an optical detector. Commercial CE-LIF systems are available as a complete, expensive package. Custom CE-LIF systems are a collection of commercially available components that meet the specific needs of the end user. Using the custom system in Dr. Woolley's lab as the standard, we hypothesized that 3D printed parts in conjunction with low-cost components could be used to significantly reduce costs and simplify the system, which in turn would make such systems more widely available with a lower barrier to entry. Testing this hypothesis began with five semesters of small teams of senior undergraduate students trying to design and assemble a low-cost CE-LIF system as part of their mandatory one-semester senior project. I was one of the seniors who worked on the system. Although none of the senior project teams were successful, a partially functioning system was ultimately produced. I reference this system as the starting point system throughout this thesis, which is focused on identifying and solving the system's obstacles in order to reach a working state. I re-designed and re-built each sub-system of the starting point system as needed if within the available budget to create a system that was functional. Budgetary constraints were included in evaluating potential improvements. The end goal was to compare the improved system's performance with that of an expensive conventional system (hereinafter referred to as the standard system) available in Dr. Adam Woolley's laboratory on the Brigham Young University campus. The ultimate conclusion of my masters' thesis work is that a low-cost CE-LIF system based on 3D printed and low-cost components results in a system that does not offer repeatable performance. In the course of my work, many lessons were learned as to what would reduce overall system costs while maintaining a user-friendly experience. My analysis is given on a subsystem basis to explain what limited the ability of the system to run consistently or what caused it to fail altogether. Details and methodology of my contributions including circuits designed, code written, components used, and 3D models printed in order to test the hypothesis are documented. Attribution of the work prior to mine is laid out when each subsystem is broken down in detail for the failure modes that prevented consistent operation. Future work is suggested to correct the problems encountered and provide a path forward to implement a next-generation system that can be achieved at a lower cost compared to a conventional system, and yet which does not suffer from the performance problems associated with the version explored in this thesis in which maximum cost reduction was aggressively pursued.

Degree

MS

College and Department

Ira A. Fulton College of Engineering and Technology; Electrical and Computer Engineering

Rights

http://lib.byu.edu/about/copyright/

Date Submitted

2018-05-01

Document Type

Thesis

Handle

http://hdl.lib.byu.edu/1877/etd10016

Keywords

CE-LIF, detection, biomarkers, laser, optics, microcontroller, high voltage

Language

english

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