Acoustic plate mode sensor for immunochemical reactions

A practical immunosensor, based on a 150-MHz acoustic plate mode (APM) device on ZX-LiNbO 3 has been build and is employed to monitor directly, in real time, antigen-antibody reactions via mass loading of the crystal surface. The results show frequency shifts ∼200 pg/mm 2 , corresponding to 8.10 8 molecules/mm 2 utilizing a typical IgG of 150 000 Da. Antigen binding capacities of aminosilane films are measured independently by a modified ELISA test and related to the APM sensor response