Experimental study of Love-wave immunosensors based on ZnO/LiTaO3 structures

Experimental study of Love-mode immunosensors based on structures of ZnO/36 degrees YX-LiTaO3 is presented, in which the ZnO films with c-axis (002) orientation have been successfully grown on the 36 degrees YX-LiTaO3 substrates by RF magnetron sputtering technique. Then the Love-mode immunosensors based on the ZnO/36 degrees YX-LiTaO3 structures and monitoring antibody-antigen immunoreactions in aqueous solutions in real time are fabricated. The experimental results show that the optimal thickness of ZnO layers is about 1.20 microm in the structures deposited on 36 degrees YX-LiTaO3 substrates, which is much less than that of SiO2 overlayers about 6 microm. The antibody-antigen immunoreaction experiments also show that the frequency shifts of the sensors with 1.33 microm ZnO films are proportional to the concentration of antigen in solution as the concentration range less than 100 microg/ml.