The Long Road Behind Us

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Since early high school I have been fascinated by nanotechnology. My first encounter with the subject was a friend of mine who told me about the concept of nanites, microscopic, autonomous machines capable of assembling anything from furniture to complex electronic devices out of constituent matter. I was not alone - this is the introduction the world was given in Drexler’s Engines of Creation back in 1986.

My second encounter, apart from the occasional glimmer in New Scientist articles, was in the computer game Call to Power II. This game is modelled on the Civilisations-style games, where the path to success is through conquest, diplomacy and research. What distinguished CtP2 from its cousins is the techtree - the Modern Age as we know it is only half way towards technological supremacy, as it is followed by the Genetic Age and the Diamond Age. Immense imagination went into the development of technologies which, according to the game’s timeline, wont exist until AD 2300. The further into the future you progressed, the greater the impact nanotechnology had on the game. Nuclear weapons are soon made non-functional by nanites dedicated to creating impurities in enriched uranium, only to replace them as the world’s deadliest superweapon, capable of reducing cities to dust.

To say that I was captivated would be an understatement. I began to look for references to nanotechnology in fiction and by futurists alike. Visions of the future surfaced in my mind, a world governed by artificial forces too tiny to see. It was clear even then that much of what was out there was nonsense, much of it entertaining, a description of technology that would not exist for decades, centuries, perhaps never. I didn’t care. It was good fiction.

Inevitably, I began to run out of absurd tales and optimistic predictions. There is only so much of the fantastic one can take before they begin to investigate the realistic. I returned to New Scientist, to Australasian Science, to American Scientist. To facts, carefully picked from cutting edge research and distilled into language I could appreciate.

It was at this point that my interest fully bloomed. It is one thing to picture the Earth in the year AD 2259 and think, “that would be amazing”. But to see what has been done, what has been achieved already, to find yourself thinking, “that is amazing”…

That is my intention here, to bring to attention some of the past achievements in the field of nanotechnology that are truly mindblowing, those that make you pause and wonder when exactly the future became the past, fantasy and speculation became standard operating procedure. These are the developments that make you quit the computer game, put down the scifi novel and pick up the textbook.

Scanning Tunnelling Microscopy

The Scanning Tunnelling Microscope (STM) has to be one of the greatest inventions of all time, just for sheer awesomeness. Certainly the scientific community thinks so – it was invented in 1981 and won the inventors the Nobel Prize in Physics in 1986, an incredibly short gap between development and Nobel Prize. The invention of the STM opened up whole new techniques in the investigation of matter at the atomic scale.

The principle behind STM is quite simple, on paper. A tip carrying a controlled voltage is moved near the surface of your sample. The closer the tip is, the more voltage bleeds across into the sample in a relationship that is well understood. The magnitude of the change in voltage tells you how far away the sample is from the tip. Scanning it over the surface allows you to analyse how the voltage changes with position, thus allowing you to build up a picture of the features of the surface. And when I say “features” I mean it is fairly common to be able to see individual atoms.

Sounds simple, but there a million little things you need to account for, first of which is the tip of the microscope’s probe. If there is any roughness or irregularities to the tip, such as multiple peaks, then you are going to receive signals from each. The only way an STM can yield quality data is if the tip is as sharp as possible, literally, as the tip comes to a peak that is a single atom in size. Constructing such a tip is not as hard as you might think: if you take a copper wire, heat it in the middle and pull, where it snaps will possibly have monatomic tips. Obviously this is crude and unreliable, but it shows that given the right technology it would be fairly easy to make monatomic tips out of metal.

The trick comes from controlling the tip. It needs to be placed at a precise height over the sample, perfect down to atomic widths, and it needs to remain perfectly stationary if necessary. Vibrations from the floor, from the motors, from the cars driving by outside would be enough to throw the tip out of its position. STMs are insulated from the ground often by cushions of air, and the tip control mechanism involves piezoelectric control systems that are somehow capable of perfect precision.

But it gets even better. Not only can people use an STM to see individual atoms, by manipulating the charge of the tip it is possible to pick up individual atoms, move them to a desired location and place them on the surface. Read that again, and let it sink in. Individual atoms can be moved, one at a time. People have made stick figures, corporate logos and kanji out of a few dozen atoms. It is also commonplace to make simple devices using this approach, but who cares about fences that can trap in electron wavefunctions when you can write your name in letters 8 atoms high?

Lotus Technology

Lotus flowers have religious significance in most places that they grow. They have the almost mystical property of remaining clean and dry regardless of the conditions. They can grow from the filthiest mud yet not have a single blemish.

Of course, any claims to mysticality are eventually confronted by science. We now know exactly why the simple lotus has this property – the surfaces of the leaves and petals are, on a very small scale, very lumpy. Each surface is uniformly laid out with lattices of lumps. These have the effect of suspending both water and dirt above the surface, allowing gravity to sweep both away. An elegant solution – once again, Mother Nature proves herself to be far better at nanotechnology than we are. But that is why one approach to the science is biomimicry, the practice of taking examples from nature and adapting them to our needs. And since we know the mechanism behind a lotus flower’s perpetual purity, it is possible to replicate it.

Right now it is possible to find clothes that repel water and stains. Originally developed for the military, there are a few commercial examples just beyond the horizon. Each of these articles of clothing mimic the uniform roughness of the lotus plant, giving them the ability to remain clean. Concrete, too, has been given this treatment successfully, and with a few other modifications it can be rendered immune to graffiti, weathering and biological damage.

It is sort of my dream project to examine whether such techniques can be applied to a transparent film. If I were to patent prescription glasses that repelled dirt, sweat and moisture I would become very rich, very quickly. Anyone reading this who subsequently creates a product like this, feel free to send me a cheque every month. You’re welcome.

Biosensors

Here is where the big money is.

Together, biosensors represent a multibillion dollar industry. Heck, blood glucose meters are examples of biosensors, and they alone would top that. Diabetes is very profitable to these companies, which is a callous way of describing it, considering they have greatly improved the lives of diabetics by increasing the accuracy and precision, while lowering the cost and blood volume needed, to determine blood glucose levels.

What was I saying? Oh yeah, biosensors. A biosensor is basically any device which uses a biological recognition molecule to detect the presence and concentration of a desired chemical. Biological recognition molecules include things like nucleotides, enzymes and antibodies, molecules that the body uses to identify specific analytes within itself.

Think about it for a moment – suppose you want to find out how much glucose is in a sample of blood. Blood is a complicated mixture, with lots of proteins, ions and the like floating about in solution. Detecting glucose in water is easy, but the other chemicals might either mask the presence of glucose or exaggerate the quantity. One approach would be to isolate the glucose from the blood, but this is time consuming, requires technical knowledge and equipment and would need a large volume of blood to get a reliable measure. A diabetic needs the results instantly, and they need to be accurate.

But enzymes are complicated proteins shaped by evolution to isolate the target chemical from exceedingly complicated solutions. They are a specific shape, and can only fit with the molecule they intend to. Similarly with antibodies – they identify foreign particles, distinguishing from native tissue by locking onto specific marker proteins. DNA and other genetic material is highly specific, bonding only to its compliment strand.

This is how a glucose meter works – enzymes specific to breaking down glucose are bound to a conducting surface, the glucose is broken down by the enzyme, which generates a current. More current, more glucose.

But that is crude, mass produced technology. Sophisticated biosensors based on antibodies have been developed capable of accurately detecting the most minute quantities. In fact, this was one of the first real life examples of nanotechnology I encountered: an Australian researcher with a lot of funds behind him developed a device he claimed could tell if someone dropped a sugar cube in Sydney Harbour. Another way of putting it is that the device could regularly detect femtomole concentrations of a target analyte, even in a solution filled with all kinds of impurities.

These are just a few of the more commonplace examples, but for me they sum up the overwhelming accomplishments already made by researchers. Even today these concepts still sound a little like science fiction, yet they are here, and have been for years. If the future has already arrived and passed us by, just imagine what is in store for us over the next few decades. If you are not amazed yet, trust me, you will be.

Comments

Nanotechnology is fascinating. Though I think in the current frame of what's going on, it is the interim steps that are the most intriguing. I am particularly fascinated by the rise of 3D printers. I think the Diamond Age will be a lot sooner than 300 years from now. I give it 100.

autonomous machines capable of assembling anything from furniture to complex electronic devices out of constituent matter
What about disassembling? How good would they be at that?

As far as I understand it disassembling is primarily an energy problem. One has to have the energy available, and the ability to channel it at scale in order to pull molecules apart.

Essentially, both disassembly and reassembly often require precise delivery of energy. But physical and biological systems do both all the time, and sometimes it is as simple as heating a whole bunch of the stuff with a lighter.

The thing is, disassembly can lead to a net release of energy, as the energy used for bonding is now free for other purposes. Now, disassebly can either occur because enough energy was injected into the system to cause permanent disassociation, or the presence of a catalyst lowered the energy required so that background levels are sufficient.

All of these are fairly simple techniques. The difficulty comes in incorporating the techniques into a nanoscale device. Though, again, both nature and humans can perform examples of this all the time.

In short, if you can assemble at these scales you can disassemble, and vice versa.

Who were the first people to start working on nanotechnology, and when did this begin? What has the military's involvement with this technology amounted to? I was under the impression that all cool stuff like this starts out as military R+D, and then comes into the mainstream consciousness; would that be right?

Quote Originally posted by ivan astikov View post
Who were the first people to start working on nanotechnology, and when did this begin? What has the military's involvement with this technology amounted to? I was under the impression that all cool stuff like this starts out as military R+D, and then comes into the mainstream consciousness; would that be right?
Probably the first example of nanotechnology is... soap.

Just kidding. Sort of. It does work on the nanoscale, and in countries like South Korea that love this sort of science, shampoo is actually advertised as boasting "nanocolloid action" ... which is true, but irrelevant.

But interestingly enough, what we would call nanotechnology today actually emerged out of acedemia. Military R&D actually jumped on the bandwagon late, as it started off as something which had only scientific interest. Scientists have been assembling things on the nanoscale for a long time, but lately there has been both the interest and the capability to do it on a grander scale, if you'll forgive my poor choice of words.

Nanotechnology originally was just mucking around with atoms, molecules and proteins. If you made something cool or even better, if you made something deliberately, you could publish a paper on it. But in its infancy nanotechnology couldn't produce much of anything beyond an idle scientific curiousity, and so remained largely an academic thing with dreams of the future.

I am generalising, though. Nanotechnology is such a broad concept at times that there would be examples of military funding stuff in the early days. A lot materials science, for example, involves adding nanoscale contaminants to metals to change their properties - something that is both relatively simple and able to produce a desirable product. But for what most people think of nanotech, the shuffling on molecules and whatnot, started off as science for the sake of science and became technology.

As a lot of science does.