Analysis of Surface Acoustic Wave Propagation Velocity in Biological Function-Oriented Odor Sensor

Abstract

We describe the measurement of surface acoustic wave (SAW) velocities to identify five odorant molecules by using a SAW device system. We derive a new frequency equation for SAWs propagating in the SAW device system with Cynops pyrrhogaster lipocalin (Cp-Lip1) protein, in order to identify five odorant molecules, R-limonene (R-Lim), ethyl butyrate (Eth), 2-isobutylthiazole (Iso), benzophenone (Ben), and 2-acetylthiazole (Ace). We developed a method to identify these odorant molecules combined with the Cp-Lip1 odorant-binding protein. Our frequency equation can satisfactorily predict different odorant molecules in the Cp-Lip1 SAW device. Moreover, our data suggest that the propagation velocity of the SAWs mostly relate to the density and concentration of the Cp-Lip1 odorant molecule mixtures. At the same sample concentration, the propagation velocity depends on the density. For the same odorant molecule, the propagation velocity decreases with increasing concentration.

Advancements in Microfabricated Gas Sensors and Microanalytical Tools for the Sensitive and Selective Detection of Odors

“…Different groups of acoustic gas sensors are reported in the literature, based on the nature of the acoustic wave and vibration modes involved. Surface acoustic wave (SAW) sensors are one of the main groups of gravimetric devices based on piezoelectric crystals, which have been widely employed for the detection of odors [ 59 , 60 ]. These devices normally consist of two interdigitated transducer (IDT) responsible to generate and receive an acoustic wave that propagates on the surface of the piezoelectric crystal [ 61 ].…”