Detection of nucleic acid hybridization with an acoustic plate mode microsensor

Acoustic plate mode (APM) devices have been used to detect the recombination of a target single-stranded DNA sample with a single-stranded DNA probe which is covalently bound to the substrate. Both single and dual delay line APM devices were designed to operate at 13 MHz and utilize a predominantly horizontal polarized shear wave in ZX LiNbO₃ in order to probe the biological overlay. The detection was performed in situ in the presence of a nonspecific DNA sequence. The APM response saturated with less than 200 ng of target DNA and was qualitatively reproducible after heating the sensor in a low-ionic-strength buffer. The results indicate that the APM sensor has the potential to detect subnanogram amounts of target DNA