Wireless Valving for Centrifugal Microfluidic Disc

This paper reports a selective wireless active valve mechanism for a centrifugal microfluidic disc operated using field frequency modulation techniques. The device utilizes a planar inductor-capacitor resonant circuit as a heater to heat up the wax-based valve in a microfluidic disc. Selective radio frequency (RF) wireless heating of the valves was utilized to control the liquid flow in the disc. A vacuum/compression valve and mixing applications using the proposed method are demonstrated in this paper. Experimental characterization shows that valve operation is within ~100 s of activation using an RF power of 1 W that provides a temperature increase up to 42 °C at a speed of 200 rpm. The reported technique offers the advantage of localized valve activation and offers a further advance in the centrifugal microfluidic area by enabling full control of liquid flow.