Microfabricated Polycarbonate CE Devices for DNA Analysis

The microchip capillary electrophoresis (CE) devices were fabricated in polycarbonate (PC) plastic material by compression molding. The molded devices were enclosed utilizing thermal bonding to another PC wafer. These thermal bonds do not yield up to an applied force equivalent to 150 psi. Aqueous fluid transport inside the plastic CE devices was enhanced by UV irradiation treatment of the hydrophobic polycarbonate plastic surfaces prior to thermal bonding. In comparison to glass microchannels, electroosmotic flow (EOF) in native PC channels is low and is independent of buffer pH at pH 7 and 9. UV irradiation of PC surfaces increases surface hydrophilicity and increases EOF. CE DNA separation was demonstrated in these PC CE devices with good resolution and run-to-run reproducibility. The on-chip PCR/CE analysis of a 500-bp region of bacteriophage lambda DNA was also demonstrated.