Many microfluidics-based lab-on-a-chip devices use external pumps and micromachined parts to move liquids through tiny channels.1 Brunnthal, Germany-based Advalytix, however, takes a different approach: Its programmable microfluidic biochips dispense with micromechanics and instead employ a technology found in cellular phones to move sample volumes along the chip's surface.
The heart of Advalytix's technology is a "nanopump" that has no moving parts and never comes into contact with reagents or samples. The pump is based on surface acoustic waves (SAW)--a technology used in communications electronics--which are generated on a piezoelectric substrate via specially designed electrodes to which a radio frequency signal is applied. The waves propagate along the surface of the substrate like a "nanoearthquake" that transfers momentum to any substance applied to the chip's surface. "This mechanical wave that's traveling on the surface of our chips really works as a kind of tiny conveyor belt," explains Jürgen Scriba, chief operating ...
