Nanotechnology

Nanotechnology comprises technological developments on the nanometer scale, usually 0.1 to 100 nm. (One nanometer equals one thousandth of a micrometer or one millionth of a millimeter.) The term has sometimes been applied to microscopic technology. This article discusses nanotechnology, nanoscience, and "molecular nanotechnology."

Potential risks

Goo

An often cited worst-case scenario is "grey goo", a hypothetical substance into which the surface objects of the earth might be transformed by self-replicating nanobots running amok, a process which has been termed global ecophagy. Defenders point out that smaller objects are more susceptible to damage from radiation and heat (due to greater surface area-to-volume ratios): nanomachines would quickly fail when exposed to harsh climates. This argument depends on the speed of which such nanomachines might be able to re-produce.

Related Topics:
Grey goo - Nanobots - Global ecophagy

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Recently, new analysis has shown that this "grey goo" danger is less likely than originally thought. K. Eric Drexler considers an accidental "grey goo" scenario extremely unlikely and says so in later editions of Engines of Creation. The "grey goo" scenario begs the Tree Sap Answer: what chances exist that one's car could spontaneously mutate into a wild car, run off-road and live in the forest off tree sap? However, other long-term major risks to society and the environment have been identified.

Related Topics:
K. Eric Drexler - Grey goo

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A variant on this is "Green Goo", a scenario in which nanobiotechnology creates a self-replicating nano machine which consumes all organic particles, living or dead, creating a slime like non-living organic mass (Green Goo: Nanotechnology Comes Alive! 23 January 2003, Etcgroup.org).

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Poison/Toxicity

For the near-term, critics of nanotechnology point to the potential toxicity of new classes of nanosubstances that could adversely affect the stability of cell walls or disturb the immune system when inhaled or digested http://www.nanomedicine.com/NMIIA.htm. Objective risk assessment can profit from the bulk of experience with long-known microscopic materials like carbon soot or asbestos fibres.

Related Topics:
Toxicity - Cell wall - Immune system - Soot - Asbestos

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There is a possibility that nanoparticles in drinking water could be dangerous to humans and/or other animals. Colon cells exposed to nano Titanium Dioxide particles have been found to decay at a quicker than normal rate(Nanomaterial hazardPhysorg.com, 4 September 2005). Titanium Dioxide nanoparticles are often used in sunscreens, as they appear transparent, compared to natural Titanium Dioxide particles, which appear white (Big opportunities for small particles 23 April 2001, CSIRO.au) .

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