A Novel Biosensor Based on Micromechanical Resonator Array for Lab-On-a-Chip Applications

Mechanical resonators are rarely reported to be used in liquid environment due to high damping. Most applications of mechanical resonators are related to their use in the gaseous environment. In this paper, a novel mass detective biosensor is proposed for Lab-On-a-Chip applications based on micromechanical resonator array. The sensor can be fabricated by MEMS technology such as standard Polysilicon Multi User MEMS Process (PolyMUMPs). The sensor consists of chained mechanically coupled resonators with electrostatic actuating elements and capacitive sensing elements on both sides. The sensor is suitable for digital microfluidic applications which an under test droplet can be led over the resonator array and affect the frequency or the phase delay of vibration. Thus, both sides of the array containing the actuating and sensing elements stay away from the droplet. It provides conditions that do not electrically interfere with the sample droplet. The vibration direction of resonators under liquid droplet is such that causes light slide film damping and does not cause strong squeeze film damping. The commercial finite element tool COMSOL Multiphysics is used to analyze the vibration behavior of proposed sensor and verify its functionality. The results are presented for the frequency response and mass sensitivity of the biosensor.