George Church and others at the Wyss Institute have apparently developed a nanorobot made of DNA which can be loaded with materials such as antibody fragments, and programmed to deliver them to certain cells.  The robot is a very, very, very tiny barrel made of DNA that opens on a hinge, and is controlled by DNA latches that reconfigure to open the barrel only when they recognize specific cell-surface proteins.

Now this may sound like someone wantonly strung a bunch of futuristic images together, but it is real!  Published in  Science today:

And the Harvard press release:

The first therapeutic application that seems to have come to researchers’ minds is cancer — effectively using the barrel to deliver a suicide mandate to cancer cells.  But it sounds like the robot itself is highly modular and could potentially be applied to a wide range of problems by varying the latch recognition program and molecular payload.  Provided it makes the leap from tissue culture to animals and hopefully even someday to humans, that is.