Highly integrated transparent microchannel chips for continuous-flow PCR

Kai Sun, Fumika Asari-Oi, Shigeki Matsuo, Hiroaki Misawa
Satellite Venture Business Laboratory, The University of Tokushima, JP

Keywords: microchannel, PCR, ITO, PS-Na, Escherichia coli HB101

Abstract:
A microchannel chip for continuous-flow polymerase chain reaction (PCR) was developed using transparent materials. The microchannel was fabricated on a quartz glass substrate using standard photolithography and wet-etching techniques, and was sealed by another quartz glass substrate. Two indium-tin-oxide (ITO) films were deposited on the etched substrate as a thermal source. A layer of SiO2 served as an insulated layer was then deposited on the ITO heaters. Next, thin ITO films served as temperature sensors were then patterned using lift-off techniques.　To confirm the temperature distribution in the microchannel, we measured the fluorescence spectra of an aqueous solution of 1-pyrenesulfonic acid sodium salt (PS-Na), which is a temperature-indicator dye, in the microchannel under a continuous solution flow. The results confirm that the temperature distribution on the microchannel’s ITO films was almost uniform (within ±2℃) under two flow rates (56 nl/min and 152 nl/min). The slightness of this deviation indicates that the ITO films integrated into the microchannel chip can be very useful as a thermal source and temperature sensor for PCR. An amplification of a 450-bp segment of Escherichia coli HB101 was successfully performed by two-stage (94℃ and 67℃) thermal cycling on the chip device.

NSTI Nanotech 2003 Conference Technical Program Abstract