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Did you come across nanobots lately?
18 Jul, 2007 02:36 pm
20 years after futurist K. Eric Drexler?s book ?Engines of Creation? describing the possibility for self-reproducing nano robots, nanobots have not become real yet. Are nanobots fiction?
Size limits: There are fundamental limits to how small things can be made. Matter is discrete, it consists of atoms and this sets the limits to how much size reduction we can achieve. Generally, scientists are aware of these limits. Even though engineers choose to ignore these limits, they have been quite successful the last 30 years in making integrated circuits smaller then we ever thought possible. One atom is about 0.1nm in size. This makes 1000 atoms per nm3 or 1000’000 atoms in 10nm3. The smallest structure realized using projection lithography today contains at least a couple of million atoms. There is certainly room to improve the size scale here but as of now, the top-down tool is not ready yet to make smaller structures possible.
Nano-assembler: Zyvex (2), is the first company that was started with the aim of building nano-assemblers; i.e., machines that are potentially capable of manufacturing bulk materials or arbitrary structures with atomic precision, getting nearly every atom in the desired place. 10 years later we witness a more modest approach from Zyvex in controlling matter at small scales. According to their website, Zyvex now, aims at simply helping customers in advanced research markets to understand the world at a different scale providing tools, instrumentation and applications. This moderate approach is also reflected in the scientific community which had distanced itself from Zyvex ‘s original vision right from the start. Building micromechanical systems (MEMS) tens of micrometers in size for sensor applications is so much more realistic.
Grey goo: Apart from being able to build small intelligent machines, K. Eric Drexler envisioned self-replicating molecular machines leading to grey goo, a world controlled by self-replicating molecular machines. Indeed molecular biology shows examples of sophisticated nano-machines, like for example, the synthesis of proteins according a specific DNA code. Fact is that scientists have a hard time in just observing one single molecule and controlling its position on a surface precisely. The vision of self-replicating machines is so far from what is happening in laboratories today that scientists look at self-replicating nano-robots as far-fetched and laughable (2).
Mixing fiction with vision: Some scientists make extreme claims what they will able to achieve. They have a vision that may be realized only in the far future. Perhaps these claims are made simply to attract long-term funding. On the other hand popular literature and cinema, targeting a large public often contain material where historic and scientific facts are mixed with fiction. This might make history or science more popular but with the danger that fiction is often confused for a proven fact. Often the uninformed viewer or reader has a hard time telling where fiction begins. We can test our critical sense by looking more closely at the images of nanobots on the internet looking like submarines. A scaled down version of a macroscopic machine will simply not work because of Brownian motion and there is underlining dynamics at atomic scales that we simply tend to ignore.
Risk in the New: While the grey goo scenario remains fiction it is important to realize that there is no research without risk. Anything new needs to be scrutinized and its impact on the environment needs to be tested. If nanomaterials can be produced by the tons and will be used in a wide range of applications we need to test and regulate what is considered safe and what not. Safety issues are instrumental for the success of nanotechnology and certainly for our future on this planet.
NanoSoccer had a debut at the RoboCup 2007 in Atlanta this month were the nanobots are viewed through an optical microscope! They are MEMS fabricated, more than hundred micrometer in size and there is nothing nano about them except their weight which ranges from a few nanograms to hundred nanograms. The playing field is 2.5 x 2.5 millimeters and watching them tells us that things are different even at this scale; the ball is not rolling anymore, and it is more like a hockey match. The ball does not slide far; friction is several orders of magnitude larger.
What can we say? We can make things small, smaller than one micrometer- on the scale of small molecules and this continues to drive today’s semiconductor industry. Yet it is very challenging to work at the atomic scale, a fraction of a nanometer. To fabricate atomically precise machines remains very challenging and we are far from any self-replication scheme of such machines.
(2) ‘Understanding nanotechnology’, S. Fritz (2002)