NANOPARTICLES

• Particles can be placed into one of three categories according to their diameter:   * Coarse particles (also called particulate-matter or dust)   * Fine particles   * ==Nanoparticles==

The diameter in nanometres used to classify particles

• Nanoparticles are between ^^1 and 100 nanometres^^ in size and usually ^^contain only a few hundred atoms^^
• Atoms and simple molecules are around 100 times larger than this
• Nanoparticles are much smaller than fine particles which have diameters of between 100 and 2500 nm
• The research into the production and application of nanoparticles is called nanoscience

  \   * One of the most interesting features of nanoparticles is their very high surface area to volume ratio   * ^^As particles decrease in size, their surface area increases in relation to their volume^^   * ^^Fullerenes (nanoparticles made of carbon)^^ behave very differently to larger compounds of carbon like diamond and graphite   * The surface area to volume ratio is an important feature in catalysis and surface chemistry   * ^^The higher the ratio then the more surface area is available for reaction, hence the better the catalyst^^

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  Nanoparticles display different properties to the same element in bulk form due to their high surface area to volume ratio*** \n ***

• Properties of Nanoparticles

  \   * ^^The main industrial application of nanoparticles is in **catalysis *^^due to their high surface area to volume ratios    Titanium dioxide in nanoparticle form is ^^used in sunscreens as it blocks UV light^^ but leaves no white marks on the skin while also providing better coverage than other sun creams   * ^^Fullerenes^^ ^^are used in medicine and drug design^^ as they are more easily absorbed than other particles and can deliver drugs to target areas more effectively   * Fullerenes are also used in ^^electronic circuitry^^ and as coatings for artificial limbs and joints   * Nanoparticles of silver are sprayed onto the fibres of medical clothing and surgical masks which gives them the flexibility of a material but with the added ^^benefit of the antibacterial properties of silver metal^^

==Risks of Nanoparticles==

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• Nanoparticles have widespread uses and applications that can provide an immense advance in materials technology
• However, the use of nanoparticles in science is in its early stages so there are still a lot of unknown factors and potential risks
• In particular there is a lack of understanding on how they may affect health
• Although there haven’t been any serious short term side effects, there could be long term side effects which we haven’t detected yet as they haven’t been in use long enough
• Even a small amount of toxicity in a particular nanoparticle would be multiplied due to the high surface area to volume ratio
• This coupled with the fact that they are not easily disposed of by the body are a cause for caution in the medical application of nanoparticles

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