A single-chip biosensing platform integrating FBAR sensor with digital microfluidic device

Although digital microfluidic system has shown great potential in a wide range of applications, a single-chip platform integrating biochemical sensors with digital microfluidic devices is still lacking. In this paper, film bulk acoustic resonator (FBAR) sensors and electrowetting-on-dielectric (EWOD) actuator are integrated on a single silicon chip, where the EWOD actuator manipulates digital droplets and the FBAR sensor detects analyte in the droplets. Thin aluminum nitride (AlN) film is a critical material as both the FBAR piezoelectric layer and the EWOD dielectric layer, which facilitates the compact integration of the two devices on a chip. A preliminary demonstration of Hg²⁺ droplet transportation and detection is conducted on the platform. The integrated platform is expected to play an important role in many complex lab-on-a-chip applications in chemistry, biology and medicine.