Hardware Design and Experimental Demonstrations for Digital Acoustofluidic Biochips

A digital microfluidic biochip (DMB) is an attractive platform for automating laboratory procedures in microbiology. To overcome the problem of cross-contamination due to fouling of the electrode surface in traditional DMBs, a contactless liquid-handling biochip technology, referred to as acoustofluidics, has recently been proposed. A major challenge in operating this platform is the need for a control signal of frequency 24 MHz and voltage range ±10/ ±20 V to activate the inter-digital-transducer (IDT) units in the biochip. A preliminary solution based on amplifiers, mechanical relays, and jump wires introduces signal loss (at least 6dB), signal coupling, and waveform distortion. In this paper, we present a new IDT-driver design that offers three major advantages: smaller form factor and lower cost, effective and high-quality signal generation and transmission, and fully-automated and flexible biochip control. Experimental demonstrations of droplet routing and a simple bioassay highlight the effectiveness of our hardware design.