| This dissertation strikes at the heart of one of the major challenges associated with developing microfluidic systems for genetic analysis---solid phase extraction (SPE) from real-world samples. The work described involves the development of a novel two-stage, dual-phase microfluidic device using a novel porous monolithic as the solid phase for high capacity DNA purification from human blood, arguably the most challenging of samples. The fundamental chemistry and microfluidic embodiment of this porous monolith is detailed, and the capacity of the monolith in the microfluidic-based device is determined as it pertains to whole blood DNA. To circumvent the competition between proteins and DNA in the blood sample for binding sites on the phase, a reversed-phase C18 pre-column is developed to selectively isolate the majority of the proteins from DNA present in the blood lysate upstream of the DNA capture phase. The enlisting of a protein capture phase as stage 1 coupled with the DNA extraction monolith in stage 2, the novel two-stage, dual-phase microfluidic device is involved. To meet the needs of clinical diagnostic community for large capacity DNA purification while minimizing the overall cost of device, a novel monolith surface passivation method is demonstrated. Finally, microchip design, specifically, the microchannel configuration and cross-sectional geometry, is optimized to efficiently eliminate DNA elution peak tailing, enabling for the faster release of DNA while still retaining the DNA concentrating effect of the SPE. Future directions are also suggested at the end of this dissertation. |
