Taste sensors utilizing high-frequency SH-SAW devices

Abstract

Recent interest in the development of taste sensors has been motivated by their potential application in the food and beverage industries as well as environmental monitoring. This paper describes the development of novel high-frequency dual delay line and two-port resonator shear-horizontal surface acoustic wave (SH-SAW) microsensors for liquid analysis. The acoustic devices have been designed to function without the need for analyte-specific coatings and to operate at the wireless ISM frequency of 433 MHz; the sensors are small, robust and are built on a piezoelectric substrate (36° YX LiTaO 3). Liquid samples are introduced to the active sensing area via a microfluidic cell that has been fabricated using microstereolithography (MSL) and then attached to the SH-SAW sensor substrate. A low cost flow system has been developed and integrated with the sensor housing to create a fully automated measurement system. Tests have been performed on aqueous solutions with different tastants representing not only the four basic tastes of saltiness, sweetness, sourness, and bitterness but also of umami and metallic. Results show that good discrimination between the different taste samples is possible using both delay-line and resonator type piezoelectric devices.