Advancing nanotechnology shrinking a world of problems

JUST IMAGINE that you take a bath and shrink by about 1.8 billion times – almost like in the 1989 movie Honey I Shrunk the Kids! If you walk into your bedroom, what you would see would not be a bed, chair, television, or people, but atoms and cells.

Reduced to the “nanoscale,” you would not only see the atoms that everything is made from, but you would actually be able to move them around! Now, if you put those atoms together in exciting new ways, like building blocks, you could build all kinds of incredible materials, everything from brand new medicines to ultra-fast computer chips and extremely strong materials.

Creating, manipulating and controlling things on the atomic and molecular level is called nanotechnology and it’s one of the most exciting and fast-growing areas of science and technology today.

However, since we live on a scale of metres and kilometres, it is quite hard for us to comprehend a world that is too small to see. Nano means one billionth (or 10-9), so a nanometer (nm) is one-billionth of a metre. To put it in perspective: a single water molecule is about 1.5nm; a strand of human DNA 2.5nm; a single haemoglobin molecule 5nm; a single bacterium about 1 000nm long; and a red blood cell 7 000nm wide. If you are a blond, your hair is probably between 15 000 and 50 000nm in diameter. If you have dark hair, its diameter is likely to be between 50 000 and 180 000 nm.

Operating at the nanoscale, scientists and engineers are currently creating new tools, products and technologies to resolve some of the world’s most burning issues, including low-cost filters to provide clean drinking water; medical devices and drugs to discover and treat diseases more successfully with fewer side-effects; lighting that uses a fraction of the electricity; and sensors to detect and identify harmful chemical or biological substances.

One of the most powerful aspects of operating in the nanoworld is that at the nanoscale the physical and chemical properties of matter change and the substance behaves differently. Copper, for instance, is transparent on the nanoscale, while gold, which is naturally unreactive, becomes chemically very active. Carbon, which is quite soft in its normal graphite form, becomes incredibly hard when it is tightly packed into a nanotube.

Although they may not be aware of it, many people are already using nanotechnology, for example wearing nanotechnology trousers, walking on a nanotechnology carpet, using nanotechnology suitcases or sleeping on nanotechnology bed sheets.

All these products are made from materials coated with “nanowhiskers.” These tiny surface fibres are so small that dirt or water cannot penetrate them, which means the underlying layers of material remain dirt-free.

If red wine is spilled on a nanotech carpet, the nano-particulate coating will keep the material from absorbing it and staining the carpet. These tiny surface fibres are somewhat akin to the 1 billion tiny adhesive hairs of 200nm on a Gecko’s toes that enable it to walk on a ceiling.

Some sunscreens use nanotechnology in a similar way: they cover the skin with a layer of nanoscopic titanium dioxide or zinc oxide that blocks the sun’s harmful ultraviolet rays. Nano-coatings are also used on scratch-resistant car bumpers, anti-slip steps on vans and buses, wound dressings and corrosion resistant paints.

Another form of nanotechnology that is quite well-known are nanochips, packed with thousands of transistors currently just 45nm wide. However, cutting-edge experiments are already developing much smaller devices that will make computers even smaller and more powerful.

A range of nanoscale materials are used in thin films to make them water-repellent, self-cleaning, anti-reflective, ultraviolet or infrared-resistant, anti-microbial, anti-fog, scratch-resistant, or electrically conductive.

Nanofilms are frequently used on eyeglasses, computer displays and cameras to protect or treat the surfaces.

The displays on cellphones, laptops and flat screen TVs are moving to organic light-emitting diodes (OLEDs), made from nanostructured polymer films providing a very high quality picture.

In the area of nanomaterials, carbon nanotubes are just as promising. These rod-shaped carbon molecules are roughly 1nm wide and 100 times stronger than steel. Carbon nanotubes are used in tennis racquets, baseball bats, and some car parts because of their huge mechanical strength and light weight. Nasa and other scientists recently suggested that carbon nanotubes could be used to make a gigantic elevator stretching from Earth to the space station.

However, it is the possibility of building incredibly small machines from individual atoms that have scientists excited.

Nanomachines could be made into nanorobots (or nanobots) that could be injected into our bloodstream to screen for cancer and infection, to destroy tumours and to remove harmful bacteria and toxins.

Also in the nanomedicine field, nanofibres were successfully used on mice to increase the growth of nerve cells and help regenerate damaged spinal nerves in a damaged brain or spinal cord.

No doubt, the future is tiny due to the continuous advances of nanotechnology in medicine, biotechnology, manufacturing, information technology and other equally diverse areas.

Professor Louis Fourie is Deputy ViceChancellor: Knowledge & Information Technology – Cape Peninsula University of Technology. Tel. +27 (011) 633-2484 Fax:+27 (011) 838-2693 Star office: 47 Pixley ka Isaka Seme Street Johannesburg 2001 | PO Box 1006 Johannesburg 2000 Website: www.independentmedia. co.za | Independent Media (Pty) Ltd

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