DNA twisted into boxes Answered
A news article in Nature reports on a group that has constructed three dimensional boxes, including a lockable lid, from DNA. Using specifically designed oligonuclitides, the boxes self-assemble chemically from long strands of DNA in solution. According to the article, "It takes only an hour or two for billions of boxes to form by themselves."
The article include both "artists conceptions" and electron-microscope images of the actual objects.
Update 13 May 2009: The Nature article above has been put into restricted access. Here is a Science News report which is not restricted.