A self-contained microfabricated nanoliter fluidic system using hydrophobic patterns and thermo-pneumatic pressure chambers

This research concentrates on developing an integrated nanoliter fluidic device for chemical and biochemical analysis. Individual components (metering unit, pump and mixer) necessary for manipulating nano liter-volume discrete liquid drops in a microchannel network are microfabricated and integrated into a self-contained device. Pre-determined volumes of liquid ranging from 1 to 1000 nanoliters are metered using a combination of hydrophobic surface treatment and air pressures. The pressures required for metering and pumping of discrete drops are generated on-chip by heating of air trapped in chambers. Pressures up to 10 kN/m2 are generated by heating the trapped air volume (100--400 nanoliters) by 30--40°C. The flow rate of the discrete drop (∼10 nl/s) is monitored by controlling the rate of air heating (∼5°C/s). Mixing of discrete drops is achieved in a few seconds by merging the drops and moving the combined drop by three or more drop lengths to interlayer the liquid across the channel depth (20--50 mum). In this dissertation, the theory and experimental results are described for each of the individual components as well as the integration of the individual components to form a self-contained integrated device.