The technique sounds promising, but there are a couple of kinks the team needs to work out. For instance, only 75 percent of the DNA molecules in one of the master’s dots are transferred to the gold. But the good news, says Stellacci, is that subsequent copies maintained the 75 percent resolution. His goal is to achieve 100 percent transfer, but he believes that in the meantime, a microarray with extra dots could yield copies with the desired number.
Another problem has to do with pressing the gold surface against the surface of the master. “When you get down to the scale of nanometers, those surfaces are not perfect. Atoms stick out of the surface, so you won’t be able to get perfect contact,” says Taylor.
Stellacci says his team is developing a prototype with more dots. “We have proven 16 [dots], and the extension to 100 seems trivial,” he says. However, Stellacci concedes that the feat will take “some serious engineering.”
Since 2003, Stellacci has received grant money from MIT’s Deshpande Center for Technological Innovation, which funds early-stage research. If successful, supramolecular nanostamping could be applied to the manufacture of inorganic devices, too. DNA strands could be used, for example, to assemble tiny particles of metal into molecule-sized wires or single-electron transistors.
“They’re on the border of a number of different fields,” says Gates, “and that’s a beautiful place to be.”