Sensitivity Estimation and Biosensing Potential of Lithium Tantalate Shear Horizontal Surface Acoustic Wave Sensor

A Shear horizontal surface acoustic wave sensor (SH-SAW) has been fabricated on 36, rotated Y- cut X lithium tantalate (36 degrees YX LiTaO3) piezoelectric substrate. Mass sensitivity investigation has been done for bound and unbound species. By using aqueous glycerol solutions with different viscosities, a sensitivity of S-1 = (2.20 +/- 0.60)degrees/(ng/mm(2)) has been found. Afterward, a biosensor has been carried out by grafting a mixed self assembled monolayer (SAM) of 1,2-dipalmitoyl-sn-glycero-3-phosphoethanolamine-N-(biotinyl)(biotinyl-PE) and 16-mercaptohexadecanoic acid (MHDA) on SAW device sensing area. Horseradish peroxidase conjugated streptavidin (HRP-streptavidin) was then attached on the SAM through biotin-streptavidin interaction. For these steps, mass sensitivities of S-2 = (6.90+/-0.70)degrees/(ng/mm(2)) and S-3 = (0.03+/-0.01)degrees/(ng/mm(2)) have been calculated. Difference between these values has been discussed in regard to existence or absence of bounds with SAW gold sensing layer on one hand, and to distance separating surface sensor from attached molecules, on the other hand.