US Patent 7163794 - Nucleic Acid Nanorobot

http://www.freepatentsonline.com/7163794.pdf

Although I have seen some suggestions of nucleic acid based nanorobots in non-patent literature (and more suggestions in science fiction) there are few patents on such technology. This patent from New York University relies on the use of set and unset nucleic acid molecules acting to move molecular "feet" along nucleic acid "footholds." Claim 1 reads:

1. A nano-robotic system comprising a molecular multiped, a molecular path along which the multiped can travel in more than one direction, a plurality of different sequence specific nucleic acid set molecules, and a plurality of different sequence specific nucleic acid unset molecules, said multiped comprising two or more feet, each of which has a sequence specific nucleic acid end and each of which is joined to at least one other foot on said multiped by a tether, said molecular path comprising a plurality of sequence specific nucleic acid footholds disposed along the path and to which individual nucleic acid foothold each foot of said multiped docks in the presence of a sequence specific nucleic acid set molecule that attaches by cohesion to both a sequence specific nucleic acid end of a foot of said multiped and a sequence specific nucleic acid foothold of said molecular path, said sequence specific nucleic acid set molecule comprising (1) a portion which is capable of attaching by cohesion to a sequence specific nucleic acid end of a foot of said multiped, (2) a portion which is capable of attaching by cohesion to a sequence specific nucleic acid foothold of said molecular path, and (3) a toehold portion which is incapable of separately attaching to either said sequence specific nucleic acid end of a foot of said multiped or said sequence specific nucleic acid foothold of said molecular path to which portion (1) or (2) of said sequence specific nucleic acid molecule can attach, wherein a foot that is docked to a foothold by a sequence specific nucleic acid set molecule is released from said foothold in the presence of a sequence specific nucleic acid unset molecule which strips away the sequence specific nucleic acid set molecule from said foot and said foothold, said sequence specific nucleic acid unset molecule being capable of attaching by cohesion to all of said portions (1), (2) and (3) of said sequence specific nucleic acid set molecule.