A hydrogen-bonded electron-tunneling circuit reads base composition of unmodified DNA

摘要

Using a tunnel junction in which one electrode is guanidinium-functionalized (to trap DNA by hydrogen bonding to the backbone phosphates) and a second electrode which is functionalized with a base (to capture its complementary target on the DNA), current vs. distance curves yield an accurate measure of the base-composition of DNA oligomers. With this long tunneling path, resolution is limited to sequence blocks of about twenty bases or larger, because of the need to form a large-area tunnel junction. A shorter hydrogen-bonded path across bases will be required for DNA sequencing. Nonetheless, these measurements point the way to a new type of nanoscale sensor.