MECHANISMS OF INTERACTION IN ACOUSTIC PLATE MODE IMMUNOSENSORS

Acoustic plate mode (APM) sensors have been used to detect immunochemi cal reactions in on-line measurements. Tn order to determine the exact mechanisms of interaction involved and to enhance reproducibility, bo th metallized and non-metallized devices have been investigated. The m etallization is found to reduce total frequency shifts by 40-50%, an e ffect which must be attributed to either acoustoelectric interaction w ith the protein layer or different mass sensitivities for the differen t surface boundary conditions. In spite of the lower frequency shifts, metallized sensors may be advantageous for detecting biochemical reac tions in ionic solutions because spurious signals are found to be effe ctively eliminated. (C) 1997 Elsevier Science S.A.