Interest in microchip capillary electrophoresis (CE) is growing due to the rapid analysis times provided and small sample input requirements. However, higher-concentration samples are typically needed because of the small (~pL) detection volumes in these devices. I have made membrane-based protein preconcentration systems in capillary and microchip designs to increase the detectability of low-concentration biological samples. A photopolymerized ion-permeable membrane interfaced with a microchannel in poly(methyl methacrylate) (PMMA) formed the preconcentrator. When a voltage was applied between the sample reservoir and the ionically conductive membrane in a capillary-based system, R-phycoerythrin was concentrated more than 1,000 fold, as determined by laser-induced fluorescence measurement. An integrated system that combines analyte preconcentration with microchip CE has also been developed using two different fabrication methods: polymerization and solvent bonding. In both approaches, microchannels within the PMMA substrates were interfaced with an ion-permeable hydrogel. When an electrical potential was applied along the channel, greater than 10,000-fold preconcentration was achieved for R-phycoerythrin. Concentrated protein samples were also injected and separated in these integrated microdevices. Membrane-based protein preconcentration devices can significantly increase the concentration range of biological samples that can be analyzed by microchip CE.
College and Department
Physical and Mathematical Sciences; Chemistry and Biochemistry
BYU ScholarsArchive Citation
Li, Yi, "Membrane-Based Protein Preconcentration Microfluidic Devices" (2006). Theses and Dissertations. 372.
Membrane, Microfluidic devices, Protein, Preconcentration, Capillary electrophoresis