Phase-changing sacrificial layers in microfluidic devices: adding another dimension to separations.

The use of polymers in microchip fabrication affords new opportunities for the development of powerful, miniaturized separation techniques. One method in particular, the use of phase-changing sacrificial layers, allows for simplified designs and many additional features to the now standard fabrication of microchips. With the possibility of adding a third dimension to the design of separation devices, various means of enhancing analysis now become possible. The application of phase-changing sacrificial layers in microchip analysis systems is discussed, both in terms of current uses and future possibilities.