I had thought that Rothemund’s DNA origami was enough to make this an unusually good year for advances in molecular nanotechnology, but now there are more advances that look possibly as important.
Ned Seeman’s lab has inserted robotic arms into specific locations in DNA arrays (more here) which look like they ought to be able to become independently controllable (they haven’t yet produced independently controlled arms, but it looks like they’ve done the hardest steps to get to that result).
Erik Winfree’s lab has built logic gates out of DNA.
Brian Wang has more info about both reports.
And finally, a recent article in Nature alerted me to a not-so-new discovery of a DNA variant called xDNA, containing an extra benzene ring in one base of each base pair. This provides slightly different shapes that could be added to DNA-based machines, with most of the advantages that DNA has (but presumably not low costs of synthesis).