Acoustic Plate Mode Sensor for Immunochemical Reactions

Abstract

A practical immunosensor, based on a 150-MHz acoustic plate mode (APM) device on ZX-LiNbOa has been built and is employed to monitor directly, in real time, antigen-antibody reactions via mass loading of the crystal surface. The results show frequency shifts ~ 1 kHz above the noise level upon antigen adsorption. The mass density detection limit of our present sensor is ~200 pg/mm2, corresponding to 8.10s molecules/ mm2 utilizing a typical IgG of 150 000 Da. Antigen binding capacities of aminosilane films are measured independently by a modified ELISA test and are related to the APM sensor response.