Development of microfluidic technologies for on-site clinical and forensic analysis: Extraction, amplification, separation, and detection

Since the concept of a micro-total analysis system (muTAS) was first proposed in 1990, clinical and forensic testing have begun to transition from macroscale sample preparation and analysis to the microscale. Using micro- and nano-liter scale reaction chambers fabricated into substrates such as glass and plastic (termed fluidic microchips), chemical processes have been miniaturized with the benefits of reduced sample and reagent consumption, cost, laboratory footprint and, in many cases, analysis time. This miniaturized technology will lead to increased portability, paving the way for on-site analysis with rapid results in the doctor's office, at the crime scene, on the battlefield, or even in space.;This work addresses the development of many facets of a muTAS, including sample preparation and analytical processes for different purposes but with the common goal of increased portability. Solid-phase extraction was adapted to the microfluidic platform for preconcentration and cleanup of spaceflight-relevant small molecules such as pharmaceuticals and radiation exposure biomarkers from biological fluids. A microwave heating technique was developed to deliver power directly to a microliter sized chamber on a microchip to rapidly control temperature in small volume enzymatic reactions with low power consumption. A sieving polymer for microchip-based DNA sequencing was evaluated and optimized for microchip-based electrophoretic separation of DNA fragments (STRs) for human identification. The sample matrix for such a separation was optimized for eventual integration with upstream processes into a single device. Finally, the detection system of an instrument constructed for microfluidic sample preparation and analysis was optimized to provide adequate detection limits and resolution for STR analysis. Data were generated, using entirely microchip-based processes, by this first-of-its-kind instrument which occupies a footprint far smaller than its conventional counterparts.