Microfluidic Genetic Analysis: Tools for Pharmacogenomics and Cell Sorting

This dissertation describes the development of microfluidic technologies for bioanalytical methods for two main applications: First, a novel assay using the polymerase chain reaction (PCR) was developed for microfluidic electrophoresis instrumentation. Warfarin has been the predominant oral anticoagulant medication for several decades despite the high risk of dangerous bleeding events associated with its use. The safety of warfarin therapy can be significantly improved by testing for genetic factors (CYP2C9 *2 and *3, VKORC1 A/B) that cause a high sensitivity to warfarin. The PCR- based assay described here allows for rapid testing that could hopefully enable physicians to genotype individual patient before giving the first dose of warfarin, which has been shown to reduce hospital visits for adverse drug reactions. The design and validation of a single-tube assay for these 3 genetic factors will be discussed. Second, a platform for cell handling using resonant ultrasound will be presented. The ability to precisely (and gently) manipulate small populations of cells could be enormously useful for emergent biomedical techniques (e.g., gene therapy for cancer treatment). When ultrasound is applied to a microfluidic device, appropriately-sized microfluidic chambers can maintain a standing acoustic pressure wave. Cells exposed to this acoustic field experience a force towards the nodes of the standing wave, and these acoustic forces can be used to trap and hold cells within a microfluidic chamber. Experimental results of acoustic trapping of bacterial pathogens and a cancer cell line will be presented. Moreover, the ultrasound intensity could be increased to induce heating by driving the system near its optimal resonance frequency. Ultrasound-induced heating was utilized both for cell lysis and for successful PCR amplification of a DNA template via thermal cycling. This multi-functional device for cell trapping, cell lysis, fluidic mixing, and PCR thermal cycling has the potential to simplify integration of bioanalytical processes need for a microfluidic genetic analysis system.