Nanotechnology

In this lesson, we will learn:

• To recall the definition of nanomaterials and nanoparticles.
• How nanomaterials are different to regular materials and why they are of interest to scientists.
• Examples of nanomaterial uses, potential benefits and risks associated with them.

Notes:

• Nanotechnology is technology that makes use of nanomaterials and nanoparticles. Nanomaterials are any materials that have a size measurable in nanometres; one nanometre is one billionth of a metre (1x10^-9 m). The practical range is 1-100 nm.
• Nanoparticles are interesting to scientists because a chemical substance can have different properties depending on if it is a nanoparticle form or not. The most interesting general feature of nanomaterials of any substance is a very high surface area to volume ratio, which generally makes materials a lot more reactive.
  • Surface area to volume ratio is a ratio of how much of the material (the atoms it's made of) are exposed on the surface of the material – surface area - compared to the total space the material takes up – the volume.
    Because only the atoms on the surface (which are exposed to other substances!) of a material can react, materials with a higher SA:V ratio are more reactive.
    • Take two identical, equal sized cubes of a material. Leave one unchanged, but cut the other in half vertically, horizontally and through the middle. You will have 8 smaller cubes of the second sample, with the same original amount/volume but a larger surface area because more of the material is exposed to the surroundings now. More of this material can now react with the surroundings at any time. See the diagram below:
  • Remember that any material can technically be a nanomaterial – it just needs to be made on a nanometre scale!
• New nanomaterials are being used in a number of products such as:
  • Sports equipment, to deliver strength whilst still being very light.
  • Sun creams that absorb UV radiation better.
  • The hollow structure of nanotubes means they could be used as 'capsules' to deliver drugs and medicines (the contents of the capsules) into the body, especially to the brain which could help research on brain-related conditions such as Parkinson's disease or Alzheimer's.
• Because a lot of the nanotechnology in use is quite new, a few concerns about its use have arisen:
  • Because of the extremely small size of nanoparticles, there is a possible risk that the particles will be able to pass the blood-brain barrier which could affect internal biological processes.
  • There is a concern that because nanoparticle use is very recent, it is difficult to know the long-term effects of exposure to nanoparticles. These findings may take years to establish.