Design by DNA
By Spencer Reiss June 2005
DNA molecules provide the architecture for all living things. New York University chemist Ned Seeman thinks they could also be a perfect assembly platform for the smallest computing devices ever built.
How do you build things out of DNA?
We don't. DNA is just a way of organizing materials on a molecular level. It's scaffolding. For instance, carbon nanotubes--how are you going to organize them into a circuit? DNA gives you a way to arrange them into something useful. Because it has a very precise structure, and because you can control how other molecules associate with it, it's just punching a sequence into a machine. And because DNA self-assembles, if there are things attached to it--micro metallic particles or carbon nanotubes--those will self-assemble along with it.
DNA's a linear molecule. Why doesn't everything you make wind up being linear?
We use a synthetic form, which we program to give us branch points. Think of the double helix as two lanes of a highway; branched DNA corresponds to intersections. You can make molecules of pretty much any shape or size you want.
What kinds of things have you made?
Lots of crystals. The earliest complex device was something that changed its shape in a controlled fashion when you added a chemical. Last summer, we did a little walker that moved across a DNA "sidewalk." Each foot was tied down by a strand of DNA. We would rip off that strand, and then the foot was free to wander around, and then we'd put in another strand to tie it down and make the next step.
How does computing come in?
As things in the computer world keep getting smaller, they're reaching the point where top-down approaches--trying to make big things smaller--are hitting the wall. What we're doing is building from the bottom up--taking little things and make them bigger. And DNA lets you do true 3-D integration. There are issues of cooling and power loss that have to be addressed, but the point is that what we're doing is inherently three dimensional, which at the nano level is pretty amazing.
So is nanomanufacturing imminent?
We are probably not going to be using this approach to knit customized sweaters. DNA is expensive stuff; for now, at least, you wouldn't want to use it for large-scale anything. But
3-D configurations of atoms, or molecules, or nanoparticles--that has to have value, in terms of making things no one has been able to make before.
What about nanotech's skeptics?
Everything we're talking about is doable. Is it doable on a scale that's going to be worthwhile? No one knows. In 25 years we've taken something that was in my imagination to the point where we can take out patents and where there are now whole conferences devoted to the topic.
TechnologyReview网5月11日消息，众所周知，DNA决定了所有生物体的结构。纽约大学化学家Ned Seeman借此认为人们同样可以利用DNA技术来组装微型计算机元件。
DNA可以从分子级控制生物体的组织结构，例如，如何把碳纳米管组成一个完整的电路？DNA技术或许就可以提供一种有效解决方案，因为它具有极其精细的组织结构。人们可以利用DNA技术控制分子之间的连接，使其成为可以运作的电子元件。
科学家们最早通过向晶体中添加不同物质来改变晶体的分子结构。DNA是线形结构，但它产生的生物体却不是线形。因此，DNA技术或许可以制造出三维电子元件。
随着计算机电子元件的体积日渐缩小，所需的工艺也日趋复杂，人们已经很难再利用传统工艺制造出更小的元件。现在科学家想办法从相反的方向考虑，他们将从分子级出发，让分子有序排列从而制造出可行的微型元件。DNA技术有可能完成这项工作。电子元件的散热量和功率一直是人们关注的焦点。纳米级的电子元件在此方面会表现出卓越的性能。
人们不可能利用DNA技术去制造一件毛衣。因为这是昂贵的制造工艺。所以，人们只可能利用DNA技术制造微型元件。并且，人们必须利用DNA技术制造出普通工艺无法做到的元件才能取得应有的价值。
没有做不到，只有想不到。问题是科学家们想到的东西是否能够给人类带来应有的价值。目前人们对这个设想是否会产生利润还不能肯定。
