Books existed well before the invention of the printing press, but they were individual, painstakingly-crafted affairs. The printing press meant that books could be assembled both more easily -- itself a revolutionary development -- and more consistently. Mass production, as we conceive of it today, has its roots in the printing press. Now that concept is set to be applied to the nanoworld.
Researchers at MIT's Department of Materials Science and Engineering Supramolecular Nano Materials Group have developed a process for "nano-printing," using DNA/RNA information transfer as a mechanism for the mass production of complex organic and inorganic molecular devices.
In the new printing method, called Supramolecular Nano-Stamping (SuNS), single strands of DNA essentially self-assemble upon a surface to duplicate a nano-scale pattern made of their complementary DNA strands. The duplicates are identical to the master and can thus be used as masters themselves. This increases print output exponentially while enabling the reproduction of very complex nano-scale patterns.
The first application will be DNA microarrays, used to diagnose and analyze genetic disorders.
[A] DNA microarray [is] a silicon or glass chip printed with up to 500,000 tiny dots. Each dot comprises multiple DNA molecules of known sequence, i.e. a piece of an individual's genetic code. Scientists use DNA microarrays to discover and analyze a person's DNA or messenger-RNA genetic code. This allows for, say, the early diagnosis of liver cancer, or the prediction of the chances that a couple will produce a child with a genetic disease.Frequent, widespread use of these devices is hindered by the fact that producing them is a painstaking process that involves at least 400 printing steps and costs approximately $500 per microarray.MIT's nano-printing method requires only three steps and could reduce the cost of each microarray to under $50. "This would completely revolutionize diagnostics," said Stellacci. With the ability to mass produce these devices and thus make DNA analysis routine, "we could know years in advance of cancer, hepatitis, or Alzheimer's."
SuNS could also be used to produce single-electron transistors, optical biosensors and metallic wires. The research is to be published in Nano Letters; a pre-release version is available to subscribers.
This is certainly cool, but to prop it up as anything more than a good way to reproduce DNA arrays is quite optimistic.
Mass production under this scenario will still require the specific separate synthesis of increasingly larger amounts of both the templating oligonucleotide(s) and the oligonucleotide(s) of interest, all with mercaptohexyl end-groups not found in nature. This means that mass production of specific arrays of DNA strands will most certainly be accessible, but that these arrays will have to be consciously designed for each application. [Please also note, for comparison to the pretty Foresight nanofactory animations, that these arrays take a relatively long time to make (multiple hours for each step).]
This is a fine piece of research, but we should all be very cautious about inflating reasonable claims from these scientists about what these assembly methods will be most useful for (genetic screening for both diagnostic and research purposes) into what would be seriously world-changing nanotechnological advances. A lot of seriously cool applications and materials have been realized through DNA interstrand interactions, but extrapolation of these principles to (cheaper, faster, more available) commodity materials has so far been elusive.
(Jamais - let me know if you could use copies of the article and/or the supplementary info and I will zap them to you.)
Transcription error? Is there a way to proof copies before releasing them? Self-correcting systems?
Good post, Jamais.
Astute comment, Grubbs.