Available at: https://digitalcommons.calpoly.edu/theses/1437
Date of Award
MS in Biomedical Engineering
Biomedical and General Engineering
Point-of-care diagnostic devices are well-suited, and typically designed, for remote and/or resource-limited environments. The obvious application is for healthcare in the developing world; however, other additional important uses exist, including for security (biothreat agent detection) and human health and research during future manned deep space exploration missions.
The objective of this thesis was to develop, and experimentally validate, techniques for improved quantified detection of labels used in lateral flow assays. Limits of detection were characterized for: (a) optical approaches, i.e., unaided eye, mobile electronic device camera images and microscope images with image analysis software developed through this thesis, and (b) a conductance based approach with direct measurement of electrical impedance in the detection region using hardware and software that were developed. Analysis of camera images from mobile electronic devices enables simultaneous detection of many targets on a multiplexed assay. Additionally, a peripheral device was designed which was intended to provide conductimetric analysis capabilities to mobile electronic devices.
The detection limit of gold nanoparticles for the unaided eye was determined at a concentration of (3.98 ± 0.40)×10-11 M; mobile electronic device image analysis, microscope image analysis, and the conductance based approach showed improvements by approximately a half to a third, an order of magnitude, and three orders of magnitude, respectively.