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View Full Version : Nanotechnology: Will it work? Arguments for and Against



SkepticJ
2005-Jan-12, 11:45 PM
Some people envision a world a century from now where nanomachines made of hundreds to millions of atoms can make anything if they are supplied with the proper chemical elements and told how to make them.
Other people thing this is an impossible pipe dream; along the lines of having flying machines that are heavier than air or splitting atoms for energy.

Some aurguments against "nanites" as we shall call them are their power source "What would power them?" The anwser depends on what kind of environment they work in. If they are outside on a sunny day perhaps solar power is an option. A machine only made of a few hundred to million atoms wouldn't need much power. If they are inside the bodies of living things they could run off of glucose. Inside individual cells perhaps ATP is the ticket. Working in a boiling temp liquid IR radiation could power them. Maybe even static electricity in certain environments.
Another argument against nanites is why haven't biological things evolved structures and abilities like nanites are hyped to one day have.
A possible anwser is that biology, at least with the chemistry like Earth life uses can't or doesn't need to. Why haven't any animals evolved turbine engines or rotor blades like helicopters for flight? Because such things would have mid stages between working and non working that wouldn't give a survival advantage. Perhaps the same could be true for nanoscale drive shafts and gears? A possibility may be that the structure of the compounds can't be synthesized so if your drive shaft is a single carbon nanotube this is beyond what current Earth biology can make. It also isn't true that microscopic organisms don't have mechanical parts. Some bacteria have something kind of like an axle where their flagellum connects to their "body". How about the protein valves in cell membranes that actively move chemicals into the cell? In fact if you think about it that's all life is, a collection of tiny machines build from atoms. Mitochondria are powerplants, chloroplasts are kind of like a solar panels that charge chemical batteries. Think of the chemical machines that read DNA. Post your arguments against or for.

mike alexander
2005-Jan-13, 06:05 AM
Power source is a problem. Ambient heat doesn't work because you can't get a temperature gradient to do useful work. Simmer or boil, it's all the same temperature. Tapping something like glucose means selective, controlled oxidation. Without belaboring it, evolution has crafted enzymes, in fact enzyme systems to carry this out. It's not simple.

Control. You have to use the power to do something. Any servomechanism needs control, and I can't see how you would stick control system on what is basicly an oversized molecule. Again, enzymes...

Here's an idea. I think the 200 atom nanobot is just too small to do anything. But there is probably enough size to provide recognition and self-assembly. You can put subassemblies of nanobots in an organism that would have affinities for a certain cell type, thus allowing them to concentrate and be taken into the cell. Then they could self-assemble into something big enough to either mimic or take over the cell's machinery to do something interesting.

Colt
2005-Jan-13, 06:37 AM
Power and control is a problem indeed. I think we'll get to extremely small machines but not insanely tiny ones made up of a few atoms. Someone has mde ane electric engine out of a few atoms if I recall though, same with a tiny jet turbine (just the turbine, none of the requisite machinery). - Colt

wedgebert
2005-Jan-13, 03:08 PM
Communication and data storage are also major problems. If you want to use nanobots to "grow" things, each machine has to know where each atom/molecule goes and what nearby nanobots are doing.

I can see them used for medical purposes though. Nanobots could be designed similar to antibodies and only target a few select targets.

eburacum45
2005-Jan-13, 03:20 PM
Some of the possibilities:

nanoassembler arrays; essentially three-dimensional printer machines of an arbritary size (much larger than microscopic) which use nanoscale positioning equipment to build three dimensional structures. Into the printer you feed ingredients, energy, information and coolant; the nanoscopic printer heads assemble the product layer by layer, creating the product to a specified degree of accuracy. These can be monolithic machines, as big as any manufacturing device nowadays; or they can be broken down into any number of subsections.
Any component which is more efficiently manufactured usng macroscopic techniques can be intoduced into the array as an ingredient.

Bionano; using a combination of genetic engineering and artificial subcellular components, modified bacteria or other microorganisms could be used to build a wide range of components; control is perceieved as a problem, but a combination of emergent behavior, distributed systems, and submicroscopic processing may allow very complex products to be manufactured under the control of a central guidance system. Modified biological systems will probably work at an efficiency comparable to living systems that have evolved naturally, although with time this may improve; the range of activity available to bionano should eventually be much wider, as it will include consciously designed features as well as evolved ones.

Self assembling machines; these are often associated with nanotech systems, but are a separate concept; the difficulties of self assembly are mostly associated with finding the raw materials and the energy to produce new machines, so much nanotech would not have the capacity for self-assembly. However if a non-biological self assembling system is ever successfully achieved, it will probably be a large assemby-line type nanoassember array, built slowly by a swarm of various sized robots; the self assembling swarm of nanobots looks like being a dream of the far distant future. Stiil; if bacteria and micobes can self replicate using a system of around a million molecules each, then this should be possible for a nonbiological system on a comparabe level of complexity (if not of scale).

This makes me think that microbots, microtechnology using of course many nanotech-sized components, is really the way forward. Before very long, in any case, it is likely that most electronic commodities will have nanotech-scale components; many do already (but these are obviously not assembed using nanobots or molecule sized motors, which seem to be a long way off).

A note on energy supply; microscopic flywheels have been suggested; this seems to be the realm of microscopic tech, if not mesotech, but it does seem to hold promise; so do radioisotope thermal generators, especially for use off planet.

TinFoilHat
2005-Jan-13, 11:14 PM
One problem that free-roaming nanobots designed to operate out in the real world would have is ultraviolet radiation. UV photos have enough energy to knock electrons loose and break molecules apart, and when your machine is the size of a cell you can only survive so much of that before breaking down. It's why prolonged exposure to sunlight burns us and kills bacteria.

Ordinary machines can survive UV light fine, but that's because they're massive things in which a few damaged molecules doesn't matter. Modern electronics can be affected by UV - part of the reason that integrated circuits are encased in opaque black plastic is to keep UV light from scrambling RAM and EEPROM memories. A machine made as small as a cell is going to have many of the environmental restrictions of actual living things.

Actually, I suspect that if we ever do build tiny nanobots designed to survive in the real world, they're going to be less miniaturized machines and more heavily modified microorganisms. Nature has a several billion year head start on us in the realm of minaturies self-reproducing molecualr engines.

eburacum45
2005-Jan-15, 02:34 AM
Here is a paper on power sources for nanomachines;
http://www.inderscience.com/garbage/f531214896107112.pdf

obviously this is a problematic area, and biological solutions may give the best early results.

SkepticJ
2005-Jan-17, 07:52 PM
One problem that free-roaming nanobots designed to operate out in the real world would have is ultraviolet radiation. UV photos have enough energy to knock electrons loose and break molecules apart, and when your machine is the size of a cell you can only survive so much of that before breaking down. It's why prolonged exposure to sunlight burns us and kills bacteria.

Ordinary machines can survive UV light fine, but that's because they're massive things in which a few damaged molecules doesn't matter. Modern electronics can be affected by UV - part of the reason that integrated circuits are encased in opaque black plastic is to keep UV light from scrambling RAM and EEPROM memories. A machine made as small as a cell is going to have many of the environmental restrictions of actual living things.

Actually, I suspect that if we ever do build tiny nanobots designed to survive in the real world, they're going to be less miniaturized machines and more heavily modified microorganisms. Nature has a several billion year head start on us in the realm of minaturies self-reproducing molecualr engines.


Fine point; however there are bacteria that live in the atmosphere above the ozone layer and they have adapted to live there just fine. There are also bacteria that somehow "paste" their DNA back together after it's been broken by radiation.

Swift
2005-Jan-17, 08:01 PM
Just my 1.3 cents worth....
I think the science fiction little nanomachines that do anything are a very distant prospect, particularly ones that do things like think collectively or build copies of themselves from any available material.

Two things that I think will happen much sooner.
1) Nano materials and devices. Not little self-replicating, do anything robots. But materials based on controlling the properties down to the nano-level (crystals with no defects, ceramics with structure and properties controlled down to the atomic level) and devices for specific functions like sensors (smart dust).
2) Designed organisms. Why build the machines from scratch, when mother nature already has done this? Modify bacteria and virus to perform specific functions, and not just biological (in the human body or in the natural environment). There is a lot of work going on to modify the high-temperature bacteria for uses in industrial environments, like chemical processing.

Chuck
2005-Jan-17, 11:17 PM
Nanotech devices can be powered by brownian motion. Molecules randomly strike the blades of a paddle wheel, sometimes trying to rotate it clockwise and sometimes counterclockwise, but the paddle wheel is ratcheted so it can turn in only one direction. The paddle wheel turns a shaft which can be made to drive other devices.

I believe I said this before. Oh, yeah. Here! (http://www.badastronomy.com/phpBB/viewtopic.php?p=142482)

SkepticJ
2005-Jan-17, 11:47 PM
So what do you think of the possibility of nanoscale mechanical parts(gears, drive shafts, worm gears, etc.)? The whole reason I started this thread was because of someone on this board who I have no animosity towards believes nanoscale mechanical parts are impossible because life hasn't evolved them beyond the aforementioned flagella axle.

Gullible Jones
2005-Jan-18, 12:07 AM
Nanotechnology already exists. Just go look in a mirror. :P

As for the artificial version... Why bother? You'd have to manufacture ridiculously complex structures of ridiculously small size from scratch in a precise fashion... Wouldn't it be easier to just tweak the DNA of some bacteria and make them do what you want, or perhaps produce what you want?

SkepticJ
2005-Jan-18, 12:25 AM
Nanotechnology already exists. Just go look in a mirror. :P

As for the artificial version... Why bother? You'd have to manufacture ridiculously complex structures of ridiculously small size from scratch in a precise fashion... Wouldn't it be easier to just tweak the DNA of some bacteria and make them do what you want, or perhaps produce what you want?

Because nanotech isn't just about tiny machines that build macro stuff but also materials that can do things far beyond what current stuff can. Think of a material that not only is a mechanical air or spacecraft part but is also a quantum computer and can heal itself if damaged. Also somethings just can't evolve, they have to be created. Think helicopters and turbofan jet engines. So we'll do both, artificial nanotech, biotech and probably hybrids of them also.

Swift
2005-Jan-18, 03:14 PM
So what do you think of the possibility of nanoscale mechanical parts(gears, drive shafts, worm gears, etc.)? The whole reason I started this thread was because of someone on this board who I have no animosity towards believes nanoscale mechanical parts are impossible because life hasn't evolved them beyond the aforementioned flagella axle.
Absolutely, nanoscale (or at least microscale) mechanical parts are possible and are being made. Here (http://www3.telus.net/norcada/) is a company that makes them, with a nice picture of some gears. But what they are used for are not little robots, but for things like probes for AFM (Atomic Force Microscopy), sensors, tiny actuators, etc. Mechanical companions to microelectronic devices.

Here (http://www.nanonet.go.jp/english/mailmag/2004/011a.html) is a great website on the mechanics of the flagella

Demigrog
2005-Jan-18, 04:00 PM
Nanotechnology is a very broad term that includes a lot of very different definitions of "nano scale". I took a class in college (http://www.phys.vt.edu/~rheflin/nanotech/) that was a very good overview of nanotechnology. The course “textbook” was a collection of journal articles--which was quite expensive because of the royalties. (http://www.phys.vt.edu/~rheflin/nanotech/coursepack.pdf -- a very good read)

Some nanotech is already in commercial products. Carbon nanotubes in particular have proven useful in LCD displays. NEMS devices like IBM’s millipede AFM storage will challenge flash memory soon. NEMS sensors are making their way into medical, security, and industrial devices. Many of these very cool nano-scale devices can be built using the same processes as integrated circuits.

Self-assembly is a term that has multiple meanings as well; in most nanotech literature, it generally does not mean that tiny machines are building things. Usually it means that a substrate material has been prepared with a pattern of chemical anchor points; the substrate is immersed in a solution containing lots of different types of molecules that attach themselves to their corresponding anchor points, basically growing a device. Defect tolerance is the key to useful applications for this technology, including data storage, sub-nanometer electronics, etc.

Nano-scale mechanical systems (with gears, motors, etc) are still generally measured in the hundreds of nanometers scale. Anything that is actually going to move is going to have wear problems, which only get worse as you scale down in size. Plus, at extreme small scales, the physics get a bit weird as forces that do not matter at macro scales start to dominate. In my nanotech class, we looked at a lot of these sorts of devices, but practical applications were still very much “sci-fi”.

Biological based nanotech is even more speculative; ATP driven motors are cool, but we still haven’t gotten past the proof of concept stage (at least in 2001; I havn’t kept up with the research). Someday, combining self-assembly with things like ATP motors and NEMS devices may allow us to create some cool stuff. IMO, it is a classic “solution looking for a problem” though. Until somebody has a “killer app” for this stuff, it isn’t going to make the leap from University to commercial product.

BTW, the first company to release a really good CAD system for designing self-assembly devices is going to be rich. Design your chemical anchor point array in a way similar to lithography today; dump a liquid solution of nano-components onto it, and watch your device grow. :) A whole industry will take off—companies selling nano-scale components, some selling substrate materials and CAD software, and some selling fab resources. I give it about 3-4 years before it takes off, 10-15 before it is as mature as lithography is today.

Swift
2005-Jan-18, 05:56 PM
SkepticJ, you're going to love this story.
cnn.com (http://www.cnn.com/2005/TECH/science/01/18/microbots.reut/index.html)

WASHINGTON (Reuters) -- Rat cells grown onto microscopic silicon chips worked as tiny robots, perhaps a first step towards a self-assembling device, researchers working in the United States reported on Sunday.

They described a new method for attaching living cells to silicon chips. They then and got the combined entities to move like tiny, primitive legs.

John Dlugosz
2005-Jan-18, 09:37 PM
Certainly nanotechnology is possible. We already have some. Besides the prototypes and experiments, note that integrated circuits quietly slipped from microscopic to nanoscopic around the year 2000.

The real question is "will we have grey goo?"

It's the same as any other technology. We have rockets that can reach the moon and other planets, but they are nothing like the rockets in cartoons and B movies. Ditto computers. Ditto medicine, material analysis, and anything else! Cartoon physics is nothing like the real world. Real-world technology will be dull and slow compared to the fiction.

--John

Doodler
2005-Jan-18, 09:57 PM
Will nanotechnology work? Depends on what you want it to do.

Arrange molecules in more controlled forms to allow the creation of stronger materials at the macro scale? Sure. Carbon nanotubes are already moving in that direction.

Allow for smaller and more powerful computers? You betcha, semi-conductors are already there and shrinking every generation. They've demonstrated nanomachines at the simplest levels, what about a microchip with the ability to cool its semiconductors at the individual level at some point in the future?

Assist in some areas of medicine? Possibly, maybe not nanosurgeons, but what about some simpler applications? A synthetic substance that can perform the role of platelets for hemophiliacs? Even smaller surgical thread that can seal a surgical wound at the smallest scales more effectively? Replacement nerve tissue? Chemotherapy drugs that are designed to be lethal only to cancerous tissue while ignoring healthy tissue?

Nanotech isn't always about micromachines, its the technology to manipulate anything at the molecular and atomic level. Synthetic fabrics that mimic spidersilk, advanced antibiotics that wouldn't come from anything in nature. If its being created whole cloth at the atomic or neara-atomic level, its a form of nanotechnology. Cripes, there's even nanotechnology in the fiber skin of modern tennis balls.

SkepticJ
2005-Jan-18, 10:22 PM
It's the same as any other technology. We have rockets that can reach the moon and other planets, but they are nothing like the rockets in cartoons and B movies. Ditto computers. Ditto medicine, material analysis, and anything else! Cartoon physics is nothing like the real world. Real-world technology will be dull and slow compared to the fiction.

I contest this. Look at the computers and technology in 1960s or even 1987-1994 Trek. We have PDAs that can do anything PADs were supposed to be able to do. Computers on Lost in Space had huge magnetic tape reels spinning etc. Sure we don't have beeming, may never, but rays that cause your sweat to superheat and explode or laser tasers already exist. They will enter service within 10 years if not sooner.
Medicine is better than some of 60s Trek also "He's dead Jim.". We're not growing new spines for people just yet but give stem cell work another 30-40 if not sooner and we'll have it. I think it's fasinating how much former sci-fi is already real or will soon be. But hey, where's my jetpack!?

SkepticJ
2005-Jan-18, 11:14 PM
Nanotech devices can be powered by brownian motion. Molecules randomly strike the blades of a paddle wheel, sometimes trying to rotate it clockwise and sometimes counterclockwise, but the paddle wheel is ratcheted so it can turn in only one direction. The paddle wheel turns a shaft which can be made to drive other devices.

I believe I said this before. Oh, yeah. Here! (http://www.badastronomy.com/phpBB/viewtopic.php?p=142482)

That's pretty creative. Did you think of that? I assume you mean just the random jiggling molecules do above 0K is what is hitting the paddles?

Here's a bit of nanotech I can't wait for--> http://www.foresight.org/Nanomedicine/Respirocytes.html

Read about the 100,000 psi version also; can you imagine holding your breath for twenty hours?

Demigrog
2005-Jan-19, 03:14 AM
Here's a bit of nanotech I can't wait for--> http://www.foresight.org/Nanomedicine/Respirocytes.html

Read about the 100,000 psi version also; can you imagine holding your breath for twenty hours?

Can you imagine being the first human to test it? :o

eburacum45
2005-Jan-19, 03:32 AM
An even more remarkable replacement for blood is the Vasculoid system;
http://www.transhumanist.com/volume11/vasculoid.html

similar to the respirocytes, but a continuous system lining the bloodvessels and replacing the blood with a continous flexible solid mass; - no heartbeat, no bleeding, resistant to trauma and capable of supporting tissue after amputation.

A sci-fi fantasy, but there you go.

Ilya
2005-Jan-19, 05:02 AM
Nanotech devices can be powered by brownian motion. Molecules randomly strike the blades of a paddle wheel, sometimes trying to rotate it clockwise and sometimes counterclockwise, but the paddle wheel is ratcheted so it can turn in only one direction. The paddle wheel turns a shaft which can be made to drive other devices.


All ratchets depend on the slight flexibility of either the wheel itself, or of the "catch tooth" which prevents it from rotating backward, or of the frame that holds both. When the wheel moves forward a geartooth slides against the catch tooth, and the smoothly increasing force pushes the two apart. Once the geartooth slid past the catch, the out-pushing force is released, and the assembly compresses to its relaxed state. Without this elasticity the wheel would not move forward any more than backward. Materials strong enough yet flexible enough to make useful macroscopic ratchets are commonplace. On nano-scale, however, molecules are either rigid -- hold their shape with forces enormous proportionally to their size, -- or bend freely. Elastic compression simply does not happen to molecules without applying forces close to those needed to tear the molecule apart -- and for Brownian motion to do that, temperature must be so high that the molecules WOULD get torn up at rapid pace. Maxwell-Boltzmann distribution would see to that. Sorry, but your "Brownian ratchet" either won't work, or will work for a few microseconds before melting.

Ilya
2005-Jan-19, 05:45 AM
Actually, I suspect that if we ever do build tiny nanobots designed to survive in the real world, they're going to be less miniaturized machines and more heavily modified microorganisms. Nature has a several billion year head start on us in the realm of minaturies self-reproducing molecualr engines.


Fine point; however there are bacteria that live in the atmosphere above the ozone layer and they have adapted to live there just fine.

Actually, they do not "live just fine" above ozone layer -- they encapsulate into spores and remain dormant, although lack of water may have more to do with that than ultraviolet light.


There are also bacteria that somehow "paste" their DNA back together after it's been broken by radiation.

True, but it is a very energy-hungry process, and these bacteria must be in a nutrient-rich environment in order to do this. More of something means less of something else.