Measurement of Temperature Induced Unfolding of DNA Hairpins by Microcantilever Sensors

摘要

The technical feasibility of monitoring DNA melting and cooling transitions using a microcantilever substrate has been demonstrated and these results were compared with those measured in solution by circular dichroism. DNA hairpins have been immobilized on the surface of gold-coated microcantilever surfaces and their DNA melting and cooling transitions were monitored by nanomechanical deflections. The hairpins comprised of a 16 base-pair GACA repeat motif stem duplex with a 29 nucleotide variable region. Microcantilever deflection profiles, measured by the microcantilever response as a function of temperature, were unique to different hairpins indicative of the molecules’ general stability and denaturation characteristics. The major melting and cooling transition temperatures for all three immobilized oligonucleotides were between 41。C - 52。C. The composition and flexibility of the DNA stem loops were shown to influence the thermal transitions.