Nanotech Motors, Biotransistors, DNA Fractals

FleaPlus writes "The American Institute of Physics has a news bulletin describing a couple of interesting nanotech advances. The first is the smallest electric motor in the world, made by Alex Zettl's group at UC Berkeley. The second is a single-protein wet biotransistor. Additionally, Technology Research News reports on algorithmic self-assembly of DNA Sierpinski triangles, by Erik Winfree's group at Caltech."

Comments

Coral Cache

[Anonymous Coward]

Take it easy on those Berkley servers. Coral Cache:

Computer-generated movie shows an artist's conception of the operation of the relaxation oscillator, and a possible application. Created by Kenny Jensen

TEM video data showing an operating relaxation oscillator, with explanatory text overlaid.

Re:Coral Cache

[Capt'n Hector]

Berkeley has a 4xOC48 line last I heard. NYU will go down before Berkeley does...

Miniature motors

[karn096]

Wasn't there an article about mini-turbines also, that researchers were planning on using to power small devices, I'm wondering if these nano-motors could be used in the same regard.
Maybe I should go RTFA now.

Help

[elid]

for those of us who aren't fond of arcane geometrical shapes (or Google, for that matter)

Eventually...

[A Sea and Cake]

The first is the smallest electric motor in the world, made by Alex Zettl's group at UC Berkeley. Eventually, this will go into the world's smallest electric planer, which will be used, in part, to create the world's smallest violin. Tragically, this wonder of design will be crushed between the fingers of Steve Buscemi.

Re:Eventually...

[karvind]

At Cornell we already made the Nanoguitar and Nano saxophone. Yes we were working on the nanodrums these days. No applications for auditions, we use very fast pulse lasers only :)

Nanoelectromechanical relaxation oscillator

[katana]

Okay, I'm not a scientist, but why would you want a *smaller* vibrating dildo?

How does it work ?

[karvind]

The peak pulsed power is 20 microwatts. Considering that the device is less than 200 nm on a side, the power density works out to about 100 million times that of the 225 hp V6 engine in a Toyota Camry.

I am not sure if I understand the power density claims. Here is a simple calculation. 20 microwatts in cube of 200nm x 200nm x 200nm will be 20 microwatts in 8 x 10^(-15) cm^3 volume. That will be a power density of 2.5 x 10^9 Watts/cm^3.

Sun's fusion power density is only ~ 2.5x10^(-4) Watts/cm^3 with core temperature around 15.7 x 10^6 K. I can understand that we wouldn't be generating the heat at peak density, but if we generate that high power desnity in nanomechanical system for even any reasonable time - wouldn't it just evaporate unless we find a very fast way of removing the power efficiently ?

Re:How does it work ?

[Anonymous Coward]

I am not sure if I understand the power density claims.

That's because they're really not meaningful. You can't compare it to the Sun (or a Toyota), because 'power density' in a macroscopic sense isn't the same thing as in the microscopic sense.

For example, if you wanted to, you could calculate the 'power density' of a single atom or an electrical current, dividing the current power by the volume of the conducting electrons. That'd certainly give you a very high number - electrons are small - but not a very meaningful one.

As slashdot says: If you're using these numbers for anything serious, you're crazy.

definition of "nano-"

[bcrowell]

Nanotechnology has gotten a reputation for being a flaky area of research. Part of the problem is that the word "nanotech" sounds cool, so people tend to use it without defining what they mean. Eric Drexler originally defined it in terms of machines that worked at the molecular level, i.e., on scales of a few nanometers. The problem is that there are fundamental reasons why it's extremely difficult to construct machines on that scale, and in the 20 years since he published Engines of Creation, basically nothing has happened to realize his original vision. Meanwhile, people have been making smaller and smaller machines via techniques that would never be able to scale down to the scales Drexler had in mind. The wikipedia article distinguishes between "nanotechnology" and "molecular nanotechnology." The Berkeley group's motor, for instance, is clearly on a scale (hundreds of nm) that is not molecular nanotechnology.

Re:definition of "nano-"

[Goldsmith]

Drexler's book was conceptually great and really pumped a lot of interest of the subject into the general public (his second is another thing). However, Engines of Creation makes a few assumptions about the molecular world which have been found to be incorrect. Diamondoids are not as stable a form of carbon at the nano scale as he thought, and materials are inherantly different from the bulk at the nanoscale. For example, a relatively inert metal such as gold becomes extremely reactive when clumped into just a few isolated atoms. The reason nothing has happened to realize Drexler's original vision is that it did not work, his detals were wrong. It's not as easy as drawing lines between carbon atoms to make the shape you want. Since then, Drexler has refined his own definition of nanotechnology into something which can be described as artificial biology in arbitrary environments. This is a common definition of nanotechnology among the majority of people who study it. Like Drexler, most of the people studying nanotechnology come from a biology background. They tend not to like the atomic or solid state approaches used by physicists and engineers, so they call their work "molecular nanotechnology" to differentiate themselves.

Zettl is a physicist, and comes at things from a very different perspective. I had the opportunity to see this research presented at an invited talk a few weeks ago at the last APS meeting. It is most definitely nanotechnology on the level of single atoms. Let me explain:

Their "motor", as presented at APS, consists of a resevior of indium atoms at one end of a carbon nanotube, and an indium crystal on the other end. By driving a current through the nanotube in conjuction with heating from the TEM electron beam, they are able to move the indium from the resevior to the crystal and back. The atoms move very quickly, they do not have the time resolution in the TEM to see them. The crystal, on the other hand, grows very slowly, and they are able to see individual atomic layers being deposited on this crystal which is only a few nanometers in diameter. The height of the crystal they can vary from nothing to microns. The whole motor is actually smaller than the smallest linear biomolecular motor (kinesin), hence the "smallest motor" claim.

Thus the fundamental technology is atoms, and is nanoscale. Furthermore, to call this technology "not nanotechnology" is absurd! This is the technique that may enable atomic construction. The ability to move individual atoms around very, very quickly and in an extremely controlled manner is essential to "Drexler's vision", as you call it. Imagine an array of carbon nanotubes, each with a resevior of a different metal at one end, which can be scanned across a surface like an inkjet printer head, depositing atoms on a surface. You would then have "atomic nanotechnology", which is what Feynman's original vision actually was.

The DNA trick is particularly disappointing

[Artifakt]

At first, I thought the DNA assembly-Sierpinski Triangle story was particularly interesting, as a link between real world information storage and the usually unworldly area of fractal geometry. On following the story, it turns out that the error rate is simply enormous (1 to 10%). DNA, in normal use, works about a billion times more reliably than it does here.
You could probably coax DNA to assemble into face centered cubic crystals with a much lower error rate than that. Hell, you might be able to get little figures of Snoopy and Garfield more reliably than these Sierpinski Triangles. This is like proving you could workably rebuild the Golden Gate bridge from Mayonaise and save the tax-payers a fortune, for sufficiently low values of "workable","fortune", and probably "Mayo".

Re:The DNA trick is particularly disappointing

[xEndymionx]

the error rate is actually rather low, the high number reported comes from error propagation. if you get a single site error, the next generation of cells below it will be computed using that error, and will thus also be erroneous. the actual number of genuine errors is rather small. winfree also has done work in error-correcting self assembly of wang tiles (which is what this really is). the key point to his generating the sierpinski gasket is that it proves that one can computer elemetary cellular automata with this dna blocks, and that includes eca rule 110, which has been proven to be universal by matthew cook. dr. winfree gave a talk about all these findings early last semester at my university.

Re:I Disagree

[Anonymous Coward]

You're talking about over 100 years' worth of innovations though - railways were invented before the Victorian age even started, and antibiotics weren't used until the 1930s.

Look around you and ask yourself if what you see was available in 1905. I'm sitting in front of a Universal Machine capable of working out any calculable problem. I can talk to anyone and everyone I know without leaving my chair. I could look at the entire human genome and check to see if I share any sections with a chicken. I can listen to a perfect reproduction of an orchestra playing halfway across the world. If I had the money, I could sit on a rocket and look at the Earth from space.

How radical do you want change to be?