MICROFABRICATED STRUCTURES FOR INTEGRATED DNA ANALYSIS

Photolithographic micromachining of silicon is a candidate technology for the construction of high-throughput DNA analysis devices. However, the development of complex silicon microfabricated systems has been h indered in part by the lack of a simple, versatile pumping method for integrating individual components. Here we describe a surface-tension- based pump able to move discrete nanoliter drops through enclosed chan nels using only local heating. This thermocapillary pump can accuratel y mix, measure, and divide drops by simple electronic control. In addi tion, we have constructed thermal-cycling chambers, gel electrophoresi s channels, and radiolabeled DNA detectors that are compatible with th e fabrication of thermocapillary pump channels. Since all of the compo nents are made by conventional photolithographic techniques, they can be assembled into more complex integrated systems. The combination of pump and components into self-contained miniaturized devices may provi de significant improvements in DNA analysis speed, portability, and co st. The potential of microfabricated systems lies in the low unit cost of silicon-based construction and in the efficient sample handling af forded by component integration.