Fabricating microfluidic devices in polymers for bioanalytica applications

Abstract

The research presented in this document focuses on the fabrication, characterization and application of microfluidic systems fabricated in poly(methyl methacrylate) (PMMA) with the emphasis focused on the fabrication processing steps. Microfluidic devices were produced in PMMA using X-ray lithography. The fabrication methods investigated were sacrificial mask, polyimide membrane mask and embossing techniques. PMMA microfluidic devices fabricated using X-ray lithography were characterized using scanning electron microscopy (SEM) and optical microscopy, while analytical techniques such as electroosmotic flow determination, separations, and fluorescent microscopy were used to characterize fluid transport in these devices. A novel method for the heat annealing of PMMA to PMMA to create a closed system is described. Characterization of this technique was carried out by optical microscopy and scanning electron microscopy. The manufacturing techniques utilized in producing mold inserts for hot embossing and injection molding is discussed as well. Both the mold insert and devices produced from the inserts were characterized using scanning electron microscopy. Devices produced can be used to perform a number of analytical techniques including single molecule detection and fluorescence lifetime monitoring. The primary goal of this research was to develop molding tools consisting of high-aspect-ratio microstructures using robust and reproducible processing steps