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Nanotechnology is a field of science that deals with very small things - objects measuring from one nanometre (one millionth of a millimetre) to 100 nanometres.
Typically, these objects are very small particles of normal materials, but they can also be molecules or clusters of atoms. A DNA molecule, for example, is about 2 nanometres wide, and viruses are about 75-100 nanometres wide. In contrast, a human hair is about 80,000 nanometres wide.
The word nanotechnology comes from the Greek word nanos (dwarf) and describes the work that scientists and engineers undertake to manipulate these minute objects to make useful products. The term 'nanotechnologies' is sometimes used to cover the many different nanotechnology applications, materials and processes that exist.
Nanoparticles can be naturally-occuring or synthetic; the term 'manufactured nanomaterial' distinguishes synthetic nanomaterials made for specific applications from naturally-occurring nanoparticles. Naturally-occurring nanoparticles can be found in the air and in food and water. Some milk components, for example, are nanosized, and traditional processes such as pasteurisation and curdling are known to change the size of these particles. Manufactured nanomaterials include:
- gold nanoparticles, used to make ruby-coloured glass since Roman times
- some of the particles in carbon black, used in tyres
- iron oxide particles in disc drives
- platinum particles in catalytic converters in vehicle exhaust systems.
Nanomaterials are not new. What is new is the ability of scientists to engineer nanoscale products and processes, and thereby exploit the properties of materials at the nanoscale. Scientists have focused on 'going small' because on the nanoscale, the properties of materials can change. Nanoscale metals and other substances produce effects that cannot be achieved using larger particles. For example, carbon nanotubes are much stronger and have far greater conducting properties than carbon fibre made from graphite. Silver, at the nano scale, has antibacterial properties, and silver nanoparticles are used in washing machines to clean clothes more effectively.
Applications of nanotechnology
Nanotechnology has a wide range of applications, and nanoparticles are incorporated in the production of many different materials and processes. For example, some familiar products such as invisible sunscreens and protective paints already use nanotechnology. Other applications of nanotechnology include:
- carbon nanotubes used in computer screens and televisions
- quantum dots and circuits in electronic devices
- coatings that improve the performance of medical drugs within the body
- protective coatings to cut glare
- rust and fire retardants
- stain-resistant clothing
- filtration of contaminated water for drinking
- hygienic food packaging
- cosmetics with skin-protection capabilities.
Future uses of nanotechnology may include:
- new ways to regenerate damaged parts of the human body, including blood vessels, brain, nerves, bone and cartilage
- drugs tailored to individual needs
- microscopic robots
- quantum computers
- intelligent clothing.
Nanotechnology research will not generally lead to specific nanotechnology products. Rather, it will lead to new ways of developing or making existing products, or by making such products cheaper or more effective, using smaller particles of existing materials or extensions of existing processes. Researchers are also looking at new techniques to make devices at the nanoscale.
The unique properties of nanomaterials will mean that they (and their applications) need to be studied for possible impacts on public health, safety and the environment.
While it might seem impossible for scientists to manipulate such tiny objects, developments in microscopy and manufacturing processes enable scientists to see and work with matter at the nanoscale.
Two main methods are used to build devices out of nanoparticles: top-down and bottom-up. The top-down method involvesetching away material to 'sculpt' the features required, such as in the manufacture of computer chips. An example of the bottom-up method is a technique by which a thin mist of atoms is deposited onto a chosen surface. This builds up a 'sandwich' of different layers that conduct electrical currents in various ways to make electronic devices such as ultra-fast computer chips.
Nanoscientists often seek to imitate nature, which has already designed strong, light and effective structures. In another bottom-up approach, chemicals are mixed and then allowed to 'self-assemble' into the desired structures, much like the way salt crystals or our teeth grow.
Issues of nanotechnology
The following health, safety and environmental issues should be considered by employers, workers, manufacturers, suppliers and regulators.
- Because nanomaterials have novel properties, consideration needs to be given to their unintentional impacts on the public's health, safety and the environment.
- Very small objects may penetrate the body more easily and may cause harm, requiring testing and regulation.
- The properties of nanomaterials may affect how materials are handled in the workplace.
- The different properties of nanomaterials may cause unwanted environmental effects (as some pesticides do), requiring testing and regulation.
- Community awareness about nanotechnology and issues related to public health, safety and environmental conditions needs to be raised.
Nanotechnology holds the promise of enormous benefits in many areas, from health and medical applications to new materials for building, and from food packaging to electronics. While embracing these benefits, we must manage any risks and provide an environment in which businesses and the public can apply nanotechnology with confidence.