Residual stress-free 100 MHz PZT-based concave diaphragm resonator for label-free protein-ligand biosensing with self-enhancing mechanism

This paper presents an innovative micromachined PZT-based concave diaphragm resonator for bio-sensing. The residual stress free acoustic transducer with strong electromechanical coupling piezoelectric material can be effectively operated at resonant and vibration modes. With conformal coated parylene as the interface of the transducer and bio-molecules, the prototype device demonstrates a high resolution (<;1 ppm) and sensitivity (0.4 (ng/ml)/Hz) when detected at 2^nd harmonic resonant frequency (100 MHz). With 200-500 kHz self-vibration enhancement, the sensitivity can be even improved ~15%. The developed transducer can be applied to many applications in biochemical related fields.