Biological investigation using a shear horizontal surface acoustic wave sensor: Small "Click generated" DNA hybridization detection

We have used a 104 MHz lithium tantalate (LiTaO3) surface acoustic wave (SAW) sensor to investigate DNA probes grafting and their further hybridization with natural and click generated (Cg-DNA) oligonucleotides. Natural DNA targets of different strand lengths, tosyl-di(tri, tetra) thymidine and azido-di(tri, tetra) thymidine oligonucleotides were tested. In our case, and besides the follow-up of a 34mer DNA hybridization, we detected complementarity between natural DNA probes and azido-tetra-thymidine for the first time, whereas previous hybridization studies reported a minimal of 10-mer oligonucleotides recognition length. We also demonstrated that contrarily to natural DNA, the synthesized oligonucleotides present stable bonds with complementary DNA strands. Frequency responses of both grafting and hybridization have shown the same shape: an exponential decay with different time constants, (187 ± 1) s and (68 ± 19) s for grafting and hybridization respectively. We have also shown that recognition between DNA strands and tetranucleotide analogues is comparable to natural 34mer DNA bases and presents the same time constant within uncertainties.