Responsible Nanotechnology

Molecular Manufacturing, in its Broadest Sense

In the last few days of technical discussion, several people have asked for more detailed information on what molecular manufacturing is and how it is supposed to work. One even asked for a short article summarizing this.

The trouble with that is that there's far too much information to put into a short article, a long article, or even a book. The best we can do is to provide an overview and answer questions.

The goal of molecular manufacturing is to use molecularly precise devices, configured as computer-controlled manufacturing systems, to make a wide range of high-performance products, including more manufacturing systems.

There are several reasons why atomically precise, sub-micron machines are desirable:

1) High functional density
2) Very high performance (scaling laws)
3) Maintenance of dimensional tolerance between manufacturing generations
4) Predictable shape -> easier automation of manufacturing
5) Zero-wear sliding interfaces (contrast with MEMS)
6) Zero static friction, very low dynamic friction

To build structures with every atom in its engineered position requires extremely high precision. This precision can be supplied by well-designed molecular machines, since all atoms of any given type are identical.

There are several reasons why multi-scale, heterogeneous nanosystems are desirable:

1) Easier interface with the macro-world
2) Tighter integration of diverse functions
3) Build complete products, not just components or materials

To build heterogeneous nanosystems requires a lot of information to be delivered to the nanoscale. This information can be delivered through computer-controlled actuators. Programmable manufacturing can build manufacturing systems with integrated nanoscale computers for even higher information delivery rates.

This overview is both high-level (stratospheric!) and incomplete. There are other desirable features, such as high-performance materials -- and nanoscale manufacturing systems built out of high-performance materials will find it easier to build high-performance materials. But perhaps there's enough here to get the idea: nanoscale programmable manufacturing systems will have lots of good properties, which will feed back to enable better nanoscale programmable manufacturing systems.

There are two main ways to do molecular synthesis under direct computer control to make engineered precise structures. One is biopolymer synthesis: DNA, protein, etc. The other is proximal probe chemistry.

DNA synthesizers can make any desired sequence of DNA by adding small molecules one by one to a growing chain. In this process, the time sequence of operations is important; the sequential choice of which molecule to add next is what controls the information content of the result. Protein synthesizers use basically the same technique, as does Chris Schafmeister's process for building stiff polymers.

In the biopolymer systems other than Schafmeister's, the structure is not directly built into the molecule. Instead, the molecule folds after manufacture to form the desired structure. DNA structures are fairly easy to predict, at least in comparison with protein structures -- but even protein structures are easier to predict for engineered sequences than for natural proteins.

Nadrian Seeman has recently built a machine that is made of DNA, is programmed by adding more DNA strands, and builds one of four product strands as desired. This is a very impressive proof of concept, although the machine cannot (yet!) build strands as complex as the strands that it is built out of.

Proximal probe chemistry controls the spatial location of reactions. As far back as 1994, the Aono Group in Japan was transferring individual silicon atoms from place to place on a silicon surface, under automated control, with error correction. A variety of individual molecules have been split and joined by scanning probe microscopes. It seems only a matter of time before three-dimensional deposition will be achieved. It should be pointed out that the scanning probe microscopes used to date have all been large, but conceptual designs exist for sub-micron probes (not just the tip, but the positioning system as well).

In proximal probe chemistry, the temporal sequence of operations is less important than the spatial position. The structure will be built directly, according to where the deposition reactions take place.

Is it possible that construction systems other than molecular machines could place enough atoms with enough precision to build useful products? It's too early to rule out that possibility, but there are some reasons to think it would be difficult. Without some kind of computers and actuators at the nanoscale, it would be difficult to deliver enough information to build intricate heterogeneous products. Without direct manipulation of molecules, the range of structures that could be built would be limited, reducing design flexibility. Without precise machines, or at least precise templates, it would be difficult to place the product molecules exactly where they needed to go.

Are there other ways than polymer buildup or proximal probe deposition to build precisely designed molecules using molecular machines? This seems likely. There are several microscopic techniques that can image atoms, and this implies that the atoms might be manipulated, and perhaps a construction technique could be based on this. It's even conceivable that some self-assembly technique could be developed that was flexible, precise, and fast enough to build products approaching the level of intricacy and performance promised by molecular manufacturing.

Do complete molecular manufacturing designs exist? No. Anyone asking for end-to-end laboratory demonstration, or even complete plans, will have to remain unsatisfied for now. The broad goal exists, along with a lot of supporting analysis to indicate that molecular machines really can be powerful enough to be worth working toward, and really can implement manufacturing systems. (We know that the polymer-based systems can work, because that's what your body uses. Positional-controlled chemistry seems more obvious to some people (computer scientists, mechanical engineers) than to others (molecular biologists), but it should work just as well if not better.

For more details, hunt through the literature, starting with Nanosystems. Some good basic articles are "Developing Molecular Manufacturing," Molecular Manufacturing: What, Why and How," and "What Is Molecular Manufacturing?" And feel free to ask questions.

Chris Phoenix

Tags: nanotechnology nanotech nano science technology ethics weblog blog

Supplying Basic Human Needs: Good or Evil?

In another thread, Tom Craver recently posted:

Giving people necessities to stay alive for a few weeks or months after they've lost everything - fine. Feeding their "basic material" needs year in, year out - bad, evil, foolish, counter-productive, flat out wrong approach.

I (Chris) disagree with the second half of this statement. I do agree that providing basic needs as charity or welfare can be corrosive. But let me suggest a scenario to explore.

1) A community is usually able to collect sufficient rainwater for its needs. In non-drought years, nature supplies its needs, with a very small amount of infrastructure work. This is very easy for the people, and certainly not evil.

2) In severe drought years (1 in 20), the community is put under severe stress. Either people must move away, or water must be imported, or people will sicken and some will die. The community does not have the cash to pay for water importation. Humanitarian delivery of water does not seem evil to me, and it seems to be covered by the first half of Tom's statement.

3) In an attempt to make water supplies more reliable, a large agricultural company installs a water system. Now the people will never have a shortage of water. However, to make the project pay, the people are required to buy their water from the corporation, and are therefore forbidden from collecting rainwater. (This has happened!) To me, this seems, at the least, unfortunate, bordering on evil.

4) In an attempt to solve the problems of 3, a new technology is provided to the community that will provide all the water they need at near-zero cost, even in drought years. 4A) This is provided to communities that don't have an installed corporate water system. 4B) This is provided to communities that do have a corporate water system. To me, both 4A and 4B seem to return to a situation very near 1, which was certainly non-evil. A modern capitalist might say that 4B was evil because it reduced the corporation's profits. I would disagree; I'd call it creative destruction, and I'd say that it would be actively good, and calling it evil is a protectionist position rather than a free-market capitalist position.

Surely no one would suggest that air should be rationed, restricted, and given only to those who would pay. Water similarly seems to be something that should be available as needed, except in cases of unavoidable scarcity. So what about food, clothing, shelter, and even medical care? What would happen if basic versions of these were made available to people, not as charity, but simply as natural resources and human rights?

The obvious, and shallow, answer is that people would breed exponentially until they swarmed past any possible technological supply of resources. But what if we added education, electricity, and (optional!) birth control to the list of freely available basic resources? Something is causing birth rates in Western nations to be even lower than needed for replacement. It seems to be correlated with energy use, affluence, and education of women. Who knows -- maybe it's TV (though I'm tempted to put TV on the "evil" list). The point isn't to design the perfect society. The point is that having basic resources freely available will not necessarily lead to overpopulation.

So, what are the assumptions behind Tom's assertion that feeding people's needs day in and day out is evil? I suspect that one assumption is that the feeding is done in the style of welfare. What if, instead, it were done by providing a certain minimum income to everyone -- rich and poor alike? The state of Alaska does this today, paying an oil dividend to all residents. Google pointed me at a site which makes a case for a "Citizen's Dividend." Rather than regulating and enforcing the provision of food, water, clothing, shelter, and so on, it might be better to just enact a minimum income and let people sort out the rest in a free market. Again, the point is not to design the perfect society; the point is that there are more options than we might expect.

Please note that there is very little of communism or socialism in this post. The idea is not to structure the state around providing the minimum supplies. Providing minimum supplies should be doable with a remarkably small fraction of government -- possibly smaller than the governmental infrastructure used to mail out the U.S. "tax refund" checks a few years ago. And in an MM-enabled society, it should be doable with a remarkably small fraction of the society's economic activity; there's no redistribution of wealth contemplated here; the minimum would be far below the average.

Looking forward to responses from Tom and others...

Chris Phoenix

Tags: nanotechnology nanotech nano science technology ethics weblog blog

Productive Skepticism, I Hope

There's been an interesting, if long, series of technically oriented comments on a recent post. A commenter named Mark Wendman has asked some technical questions about how molecular manufacturing (MM) might work, and made some rather skeptical assertions.

In one comment, he refers to "Positional drift, Tip durability / lifetime, positional verification, solid phase desorbtion source - stochastic emission and gas phase - beam induced polymerization scattering??" as possible problems. And in a later comment he expands on four of these points.

The discussion is interesting for several reasons. First, it shows how easily people can talk past each other, and even take offense. Second, it shows how a skeptic can criticize off-topic proposals without ever realizing it. This is an ongoing problem for MM, because there are a lot of things that won't work, and a skeptic who thinks the non-workable ideas are what's been proposed for MM will go away convinced that we're a bunch of shallow flakes.

Mark's objections deserve an answer, and rather than bury it at the end of a long comment thread, I (Chris Phoenix, CRN's Director of Research) will post it here.

First, some background, because Mark seems to be starting from some incorrect assumptions.

1. Molecular manufacturing proposes to build a form of scanning probe microscope on a sub-micron scale. Early in the thread, there was some inconclusive discussion of scalability and exponential manufacturing that wandered into present-day diamond manufacture -- quite off-topic. I'm not sure Mark has realized that we are talking about such radically different and smaller SPM architectures. Since the time for an SPM to process its own mass in atoms decreases as roughly the fourth power of the size, a 100-nm SPM should in theory process its own mass in about 100 seconds.

2. MM does not plan to build *every* substance or *every* product. However, it proposes to build a reasonable subset of highly crosslinked carbon-backbone covalent solids, in programmable shapes and with atomic precision. This should be enough flexibility to implement nanoscale machines (such as SPM's) and to implement a fairly wide range of micro- and macro-scale material properties.

3. Probe-based MM (as opposed to polymer-based MM, a whole different topic that we're not even touching on there) probably depends on knowing where all the potentially reactive atoms in the system are. This is a stringent constraint, which may appear impossible in comparison to today's technologies -- but we can have a conversation about that. And if this condition can be achieved, it implies a lot less need for scanning/sensing and computation than exists in today's research systems.
   

Mark's first objection: Positional drift. In today's SPM systems, this is a major problem. There are several reasons for it, including properties of piezoelectric elements that will not be relevant, and thermal distortion of large systems that will be less relevant. (Thermal noise is not a source of drift, but instead a source of uncertainty. Any SPM system will have to deal with thermal noise, but so far it looks manageable, especially at moderate cryogenic temperatures.) Positional drift is a major reason why SPM systems need to re-register their position. A system with no drift should be able to skip that.

Mark's second objection: Tip lifetime. In today's systems that scan unknown and dirty surfaces with tips that are crudely structured at the atomic level, the tips gain and lose atoms pretty frequently. But would there be any wear if a buckytube tip were scanning a graphite sheet in a perfectly clean system? This is probably closer to the conditions that would exist in the hypothetical MM system. Mark, do you know if there is any experimental data on tip wear in clean graphene-on-graphite scanning? Perhaps the graphite-on-graphite superlubricity experiments, in which entire sheets pass each other with low friction (does this indicate absence of cross-linking?) might also indicate hope for low-wear contact.

Mark's third objection: Using the tip as the source of atoms will cause imprecision and tip wear. In today's systems, either the tip structure is the source of atoms, or the atoms (molecules) are adsorbed on the tip--not chemically bonded, but free to move around. In MM proposals, the tip would incorporate a precise structure containing one or a few atoms; would deposit those atoms, leaving a precise structure; and would then be recharged (have the atoms replaced) before the next deposition operation. No system today does this, and as far as I know only Freitas's proposal contemplates doing anything like this with today's technology. Deposition from a single precisely known molecular structure that's designed for that purpose can't be compared with today's deposition results. It should be criticized on its own merits.

Mark's fourth objection: Tip-mediated or beam-mediated deposition of atoms from gas is quite imprecise. I completely agree, but this has no relation to molecular manufacturing proposals. (It may relate to some bootstrapping proposals that are intended to make small, useful, imprecise structures. But it does not relate to post-bootstrapping exponential-manufacturing plans, which are the plans that deserve the most skepticism.)

Another objection that Mark made elsewhere in the thread was that surface-adsorbed atoms are mobile even at liquid helium temperatures. This is true, but MM does not propose to use adsorbed atoms. All the reactive atoms are intended to be covalently bonded to either the tip or the workpiece. Covalently bonded atoms are not mobile even at room temperature.

I hope that Mark will find these responses constructive. There are several responses he could make.

1. "I refuse to believe that you can solve the practical problem of ______ so I will remain a critic." This answer ends the conversation. Possible ______'s include sub-micron SPM's (including actuation, but not including the control computer), contaminant-free workspaces, and doing carbon-lattice mechanosynthesis reactions reliably.

2. "I don't see how you can do ______ (or be sure of ______) because ______ so you have to anwer that." If I get this response from Mark (or almost anyone else), I will answer it.

3. "Oh, I guess I have to learn more about the actual proposals before I criticize them." Eventually, I hope to get Mark (and other skeptics/critics) to this position.

4. "I can prove that ______, which is necessary to your plans, is impossible." I would be extremely surprised at such a response, because no one has found a showstopper in over two decades of trying, and some very smart people have tried.

5. "You have to prove that _______ is possible before I will listen to you." Like the first response, this ends the conversation.

I hope that this conversation will be productive.

Chris Phoenix

Tags: nanotechnology nanotech nano science technology ethics weblog blog

NanoNews-Now: Special Issue

Nanotechnology Now announces:

Special Issue!

As a thank you for your support of our publication we are offering this month's NanoNews-Now premium newsletter for free!

In this issue we cover Molecular Manufacturing. Editor Rocky Rawstern interviews Mike Treder and Chris Phoenix of the Center for Responsible Nanotechnology.

In a second article by science writer Brian Wang, we learn about "Possible Futures." [Note: This is a nice companion to the BT Technology Timeline.]

And in the second of six articles on Building The Winning Nano Venture Team, Bo Varga covers "Building the Winning Start-Up Team."

You can access this month's free issue here. (Current subscribers who have already paid this month's subscription fee will receive their next issue free of charge.)

For a 90-day free trial subscription to NanoNews-Now report, sign-up here.

Enjoy!

Tags: nanotechnology nanotech nano science technology ethics weblog blog

A Grand Milestone for CRN

I just noticed that the previous post was #1,000 on this blog. We started in January 2004, so that works out to about 40 posts a month on average, although we did fewer earlier and more now.

You, our wonderful readers, have submitted over 5,000 comments in the last 26 months, and we truly appreciate them all. This has become a wonderful way to stay in close contact with a community of people who care about the future.

We are now receiving more than 30,000 hits per month; more web sites link to Responsible Nanotechnology than to any other nanotech blog; and we were honored to be named recently by CNET News as one of the 100 blogs most worth reading -- out of nearly 30 million to choose from!

A thousand thanks to all of you for your support. We hope you will continue to find our blog "worth reading," and if you have suggestions on how we can become even better, please let us know.

Mike Treder, Executive Director

Tags: nanotechnology nanotech nano science technology ethics weblog blog

Nanotechnology Law

If you're interested in international law, particularly as it relates to nanotech (both current and future), you really should be reading the Nanotechnology Law blog. Mohamad Mova Al 'Afghani, an attorney in Indonesia (and a member of the CRN Task Force) has posted a number of  interesting and informative articles there. We're expecting even more valuable contributions from him as time goes by.

Mike Treder

Tags: nanotechnology nanotech nano science technology ethics weblog blog

Technology Timeline

We're a little bit late on this item. Some of you may already have seen it. But just in case...

The 2005 BT Technology Timeline

This an annual compilation, edited by Ian Neild & Ian Pearson of British Telecom (BT). Invariably, it arouses many comments, some skeptical or critical, some supportive, and a few dismissive. But as the Ians say:

[We] are not involved in all of the research described in the timeline. We also do not necessarily approve or condone what we are predicting will happen. We are just saying they are possible, and listing some obvious implications. . .

In the next 60 years we will see nanotechnology and biotechnology making impacts on our life that might seem like magic to us but will be quite normal to our children's children. The world is speeding up as each generation learns from their kids, and through knowledge sharing via the Internet, so who knows what the next 60 years will bring? Our timeline can only cover a small sample of what is coming.

So what is coming, according to their timeline?

Let's look at just a few of the hundreds of predictions [PDF] they have compiled:

2006-2010: AI chatbots indistinguishable from people by 95% of population
2006-2010: Emotion detection used in businesses to select front line staff
2008-2012: Insect-like robots used in warfare
2008-2012: Intelligent materials with in-built sensors, storage and effectors
2008-2012: Terahertz video cameras become social nuisance due to privacy invasion
2011-2015: Insect-like robots used for crop pollination
2011-2015: Commercial magma power stations
2011-2015: Academic learning is argued to be unnecessary in the age of smart machines
2011-2015: Electronic stimulation of brain sensations as recreational substitute for drugs
2011-2015: Orgasmatron
2011-2015: Materials exhibiting superconductivity at room temperature
2013-2017: Hotel in orbit
2013-2017: Terrorist use of GM to pollute crops and damage economy
2013-2017: Manufacture of long diamond fibres
2013-2017: Bacterial supercomputer
2016-2020: Human knowledge exceeded by machine knowledge
2016-2020: Fully auto-piloted cars
2020s: 3D home printers
2020s: Nanobots in toothpaste attack plaque
2020s: Smart yogurt, colony of smart bacteria linked together, IQ = human [!]
2020s: Digital image overlays enhance relationships
2020s: Global voting on some issues
2020s: Full direct brain link
2020s: Network based telepathy
2020s: Creation of The Matrix
2020s: More robots than people in developed countries
2020s: Android gladiators
2020s: Gated cities for civilised people
2030s: Space solar power stations
2030s: Use of solar wind deflectors to set fire to cities
2030s: Regular manned missions to Mars
2030s: Use of human hibernation in space travel
2030s: Space elevator based on carbon nanotube cable
2040s: Use of nuclear fusion as power source
2040s: Self sustaining Mars colony
2040s: Asteroid diversion used as weapon

It's easy, of course, for any of us to pick items that we think will happen sooner than they predict, or later, or not at all. Overall, however, it's an impressive accomplishment, although their omission of nanofactory development and implications is a major weakness.

Some of their entries are a little silly or nonsensical, such as:

2016-2020: AI Member of parliament
2020s: AI Entity gains PhD
2020s: AI Entity awarded Nobel Prize
2020s: AI entities given vote

An AI smart enough to earn a PhD or win a Nobel Prize should be able to rapidly improve its own programming and reach an exponential rate of intelligence growth in a relatively short time. When that happens, then all the other predictions are likely to go out the window.

Also, does it make sense that an AI is elected to parliament before AIs are given the vote?

Mike Treder


Tags: nanotechnology nanotech nano science technology ethics weblog blog