Template-synthesized DNA nanotubes.

There is considerable interest in DNA-functionalized nanotubes with proposed applications that include use as gene delivery vehicles, in DNA-assisted separation and assembly of carbon nanotubes, and in nanotube-based DNA sensing and separations. In all of these previous cases, the DNA molecules were attached to a nanotube composed of a second material, typically carbon; however, it might also be advantageous to have nanotubes composed entirely, or predominately, of DNA itself. We describe here a template synthesis method for preparing such DNA nanotubes. The synthetic strategy builds on prior work, where we used Mallouk's layer-by-layer alpha,omega-diorganophosphonate (alpha,omega-DOP) Zr(IV) chemistry to deposit layered alpha,omega-DOP/Zr(IV) nanotubes along the pore walls of an alumina template membrane. The DNA nanotubes described here have an outer skin of one or more of these alpha,omega-DOP/Zr(IV) layers, to provide structural integrity, surrounding an inner core of multiple double-stranded DNA layers held together by hybridization between the layers. The DNA molecules comprising these nanotubes can be varied at will, and the DNA can be released from the nanotube by melting of the DNA duplexes comprising the nanotubes.