AN ACOUSTIC PLATE MODE BIOSENSOR

A prototype biosensor, which utilizes an acoustic plate mode (APM) in a piezoelectric crystal plate as the sensing element, has been designed, fabricated and tested. The APM is selectively excited and received by aluminum interdigital transducers (IDTs), which are fabricated on a Z-cut X-propagating lithium niobate (ZX-LiNbO3) substrate using standard photolithographic techniques. The biological film is bound to the face of the ZX-LiNbO3 plate opposite to the IDTs. Appropriate r.f. electronics are used with the APM device to form the complete biosensor. Tests relating to the detection of deoxyribonucleic acid (DNA) hybridization demonstrate that the biosensor exhibits a high level of sensitivity, selectivity and reproducibility.