Surface Acoustic Waves Sensor for DNA-Biosensor Development

A 104 MHz LiTaO3 shear horizontal surface acoustic waves sensor (SH-SAW), working in a dual delay line configuration, was used to design a DNA-biosensor. Grafting of 27-mer oligonucleotide probes on the gold covered LiTaO3 crystal surface, and successive hybridization cycles with 36-mer oligonucleotide targets, were successfully achieved. Grafting and hybridization efficiency measured are consistent with those reported with other physical sensors. The device mass sensitivity, of 6.3 Hz/ng, is in the range of quartz microbalance bulk acoustic wave sensor (QCM-BAW) detection limit. Technical development of SH-SAW sensors is a major challenge for label-free DNA detection, as such devices, widely used in mobile and wireless communications, can reach several GHz frequencies.