Disposable digital micro-fluidic system using surface acoustic wave devices

A droplet manipulation is one application of a surface acoustic wave (SAW) device. If a sensor fabricated on the SAW device, a digital microfluidic system is realized. For disposable application, three-layer structure of sensor plate/water layer/128YX-LiNbO3 was proposed. In this paper, first, an enzyme reaction is measured using the system. An interdigital electrode (IDE) is fabricated on the sensor plate which is glass plate. Urease droplet on the plate is manipulated and mixed with an urea droplet. Then catalytic reaction of the urease is measured. Second, an acoustic streaming which is generated is observed. Streaming velocities at different thicknesses of the glass plate and water layer thickness are compared. The results indicate that efficiency of droplet manipulation is improved by using a thin glass plate.