Ultrasonic plate waves for biochemical measurements

Abstract

Flexural plate waves can propagate non-radiatively along liquid-immersed plates provided the plate wave velocity is lower than the speed of sound in the liquid. This low-loss condition has been exploited to measure biochemical processes in liquids. Proteins or other biomolecules that adsorb to the plate surface lower the plate wave velocity, while the viscosity of the liquid causes attenuation of the plate wave.Thin plate-wave structures have been formed with microfabrication techniques. The response of these structures has been experimentally calibrated and found to agree well with theory. The plate-wave delay-line oscillator tested has a mass sensitivity which permits the detection of less than ten nanograms of mass adsorbed over the 0.24 cm2 membrane area. Fluid viscosities were measured in the range of zero to 10.6 poise.The plate-wave delay-line oscillator frequency was monitored to study the adsorption of protein onto the Sensor surface in real time. Plate wave attenuation was seen to rise sharply over time as a drop of blood on the sensor coagulated.

Surface Generated Acoustic Wave Biosensors for the Detection of Pathogens: A Review

“…By the same time, Constello et al . [112] monitored the changes in frequency and viscosity of such devices over time, when proteins adsorbed onto the sensor surface.…”

High frequency shear horizontal plate acoustic wave devices

“…These fundamental wave modes have attracted much attention because they posses a number of attractive properties. A number of investigators have studied the A 0 and S 0 waves, mainly for sensor and actuator applications [2][3][4][5][6][7][8]. On the other hand, the work in our laboratory has focused mainly on the SH 0 wave.…”

Sensing liquid density using resonant flexural plate wave devices with sol–gel PZT thin films

“…Laurent et al (2000) addressed the configuration design of the FPW devices using AlN and ZnO on silicon membrane, indicating that the FPW device has a greater mass sensitivity than other acoustic devices. Costello et al(1989) developed a simple theory for the mass sensitivity of a delay-line oscillator with ZnO on a silicon nitride membrane, and modeled the attenuation of plate waves in contact with viscous liquids. Weinberg et al (2003) derived the fluid-damping model of resonant FPW devices.…”