Nano-Scale Robot Arm Moves Atoms With 100% Accuracy

destinyland writes "A New York professor has built a two-armed nanorobotic device with the ability to place specific atoms and molecules where scientists want them. The nano-scopic device is just 150 x 50 x 8 nanometers in size — over a million could fit inside a single red blood cell. But because of its size, it's able to build nanoscale structures and machines — including a nanoscale walking biped and even sequence-dependent molecular switch arrays!"

"Success Rate" not "Accuracy"

[michaelmalak]

"100% Accuracy" implies a positional error of zero meters (to infinite decimal places), which is obviously not what they're talking about. Amazingly, this mistake is not just in the Slashdot summary, but in the cached [74.125.47.132] FA as well.

If we go to the referenced Nature article abstract [nature.com] we see that the development "yields programmed targets in all cases."

The correct terminology then would be "100% Success Rate" not "100% Accuracy".

P.S. Presumably "success" is defined by something like "90% Accuracy", to put an ironic spin on it. But it makes no sense to speak of accuracy in terms of percentage without a reference, such as "a single atom". So the criteria was probably something like X nanometers accuracy.

almost a year old

[snoop.daub]

The Nature Nanotechnology article is almost a year old. There are lots of people working on similar stuff, here's a review which mentions the Seeman work among many others (you probably need a library subscription to see the article, but the abstract should be accessible at least):

http://journals2.scholarsportal.info/details-sfx.xqy?uri=/14394227/v10i0015/2420_catdn.xml [scholarsportal.info]

Heisenberg applies to everything

[wurp]

But it's about *momentum* versus position. The more mass something has, the smaller the minimum product of the uncertainty in the *velocity* & position.

h >= dp * dx / 2 * pi

where dp is uncertainty in momentum; momentum is mass times velocity.

Re:Question:

[blincoln]

Can they make gold?

This device manipulates atoms and molecules, not individual protons and neutrons within the nucleus of an atom. So no, it can't make gold out of another element. You can do that with nuclear reactions if you want to live the alchemists' dream.
It's still really amazing. I wish Feynman had lived to see it.

Re:Misleading headline

[MozeeToby]

Actually, the article is about using a DNA strand to place individual atoms where you want with a 100% success rate. Basically, its using the DNA strand as a robotic arm, in that it does exactly what you would expect a robotic arm to do.

Re:Did we just break heisenberg's principle?

[martas]

i don't know why this is rated funny, but it's true. even your table has wave-like properties, and theoretically it could be passed through a diffraction grid, and you'd get cool positive/negative interference of the table with itself if you put a wall on the other side of the grid. the only problem is that the table would have to move very slowly...

Re:Just a thought.....

[Anonymous Coward]

In order to break the bonds, the assembler (disassembler?) would need to impart sufficient energy into them, in the form of momentum (technically heat, but at the scale of one atom it's easier to think about movement). The bonds are held in place because the shared electrons are in a lower energy state; as long as they have enough momentum they can reach "escape velocity" (yes, it's not velocity, but it's a good analogy) the atoms would separate.

IANAP, but I got As in quantum mechanics and chemistry :p

Re:Just a thought.....

[MozeeToby]

It's still a chemical reaction, it's just a very precisly controlled one. You would still have to add energy to break the bond in a molecule of CO2. I suspect that if someone goes through all the trouble to do that, they'll have it produce diamonds instead of pencil lead, since at least then you can sell the result and maybe make a bit of profit off of it (though not for long, what with economies of scale and everything. If this is really possible in large scale diamond will be cheaper than glass someday).

Re:Just a thought.....

[martas]

well, you can never cheat a molecule out of its potential energy, so of course this would still apply. however, maybe this method would be more energy-efficient that chemical methods of achieving the same thing, although i have no idea if this is the case or not.

Re:Question:

[martas]

no, they can't make gold, because they don't move elementary particles, they move atoms. gold is an atom, hence they'd need gold to make gold, which isn't a very impressive feat. what would be cool is if they could take simple graphite (pencil lead), and assemble it into diamonds, and make the whole process significantly cheaper than diamonds are today. it could be a real game-changer, and i'd really enjoy seeing diamonds that now cost millions of dollars lose almost all their value, thus screwing over anyone who has made large investments into diamond jewelery. something like this happened with aluminium - it used to be a very expensive metal, because it was difficult to extract it from the ore, so there was a lot of aluminium jewelery. then some guy came up with a new way to extract it, and it became the cheap-ass metal we all know and love today.

Re:Heisenberg applies to everything

[jlintern]

h >= dp * dx / 2 * pi

Modded informative? This equation is backwards.

h is a lower bound on certainty, not an upper bound.

Re:Heisenberg applies to everything

[HeckRuler]

no one said that +5 informative means +5 truthful. In this case we are pleasantly informed of something where the majority of it is true.

Typo: I wrote the inequality backwards

[wurp]

Ack!! Thank you!

h <= dp * dx / 2 * pi

is of course the correct equation. Note that the text was correct; I just fat-fingered the inequality.

No Grey Goo...

[tylorsan]

Not a nanobot, but perhaps another tiny incremental step toward positionally controlled chemistry. I can't get to the core Nature article, but it looks like they make a DNA tile cassette, which they can insert a variety of DNA tooltips into. They probably get ~1-10 nm positional accuracy between tooltips. Not precise enough or controlled enough to do diamond mechanosynthesis, but possibly an interesting route to bootstrapping into that kind of technology. As per usual, the biggest problem is that DNA isn't particularly stiff, making it hard to apply the kinds of forces at picometer precision that seems necessary for the sci-fi nanotech visions. Variations of this technology may prove useful in designing and building/folding artificial proteins or biomolecules. With biomineralization, that might eventually provide the stiffness and strength necessary to start beating nature at this mechanosynthetic game.

Terrible, Terrible Summary

[TeethWhitener]

Mr. Anissimov (author of TFA) has either dumbed the science down too much or simply doesn't understand what's going on. I'll try to give a summary of the Nature Nanotechnology paper as clearly and concisely as possible.

First, the researchers made a nanodevice with two slots that could accommodate so-called "DNA cassettes" in a programmable way. The DNA cassettes themselves have free ends that can only bond with complementary DNA. Each of the DNA cassettes has an 'A' end (that can only bond with other A-type molecules) and a 'B' end (I'm simplifying this greatly; 'A' has nothing to do with adenine). The cassettes can be inserted into the two slots with either the 'A' end up or the 'B' end up. So this means there are a total of four states for the device: (1) first slot: A up, B down; second slot: A up, B down; (2) first slot: A down, B up; second slot: A up, B down, etc. The researchers were then able to take four target molecules (one for each of the four programmable states) and show that they bonded to their complementary state. Further, by developing an error-correcting scheme, they were able to get the fidelity of the bonding to 'apparently flawless' levels (quoting FTA, more on this in a sec).

A little more explanation is in order. All of the target molecules have an 'A' and 'B' marker on both ends of their strand. Now, say for example the nanodevice is in state 2: 1A down, 1B up, 2A up, 2B down. The complementary molecule to bind this state would have four markers with 'A' oriented downward and 'B' oriented upward on one end of the strand, and 'A' orented upward and 'B' oriented downward on the other end of the strand. The problem with this is that other target molecules which aren't complementary can still bind. For example, the target for the 1A up, 1B down, 2A down, 2B up would fit equally well into this binding pocket upside down. Also, any of the target molecules can bind with half of the binding pocket, leaving the non-complementary end either dangling or only loosely bound. The researchers get around these two problems using their error-correction scheme. It turns out that the correct target molecules bind more tightly to their complements than the incorrect ones. By heating the devices slightly, the researchers can dissociate the incorrect binding while keeping the correct binding intact. This is, I believe, what was meant by the phrase '100% accuracy.' So, in short, it's still exciting research, at least from my point of view, but no one's moving individual atoms with 100% accuracy or any of the hyper-exaggerated nonsense that I've been reading here.