The Potential of the Bulk Acoustic Wave Device as a Liquid-Phase Immunosensor

Abstract

A summary of previous experiments is presented, which is concerned with partial immersion of bulk and surface acoustic wave devices in liquid media in order to produce chemical sensors. The the- ory of kinetics of antibody-antigen complexation at a planar surface is described together with a qualitative treatmen't of the propagation of acoustic shear waves through the interface between the solid device and the bulk liquid. Surface treatment of a bulk wave crystal by Lang- muir-Blodgett film technology and by silanization is employed to dem- onstrate that the structure of the interface is important in determining the time-dependent frequency of the device. Immobilization of antisera to the crystal-electrode surface by two different methods is used to examine experimentally the response of the device to interfacial reac- tion with an antibody. The future potential of liquid-phase acoustic wave sensors is evaluated.