Gold's potential as a cancer treatment and for mending arthritic lions
By: Rhona O'Connell
Posted: '12-DEC-05 13:11' GMT © Mineweb 1997-2004
LONDON (Mineweb.com) -- At the Euromoney Gold Investment Summit in London last week, Dr. Richard Holliday, Head of industrial applications at the World Gold Council gave a paper on the industrial and commercial uses of gold, commenting at the outset that this area doesn’t get too much attention. So, here is some attention!
Gold’s industrial applications pale into insignificance in the public perception because of the romance of jewellery and investment. They are, however, important, not only because they comprise over 500 tonnes of global gold demand (i.e.16% of total physical fabrication in investment bar demand), but also because there are areas in which gold is essential to the smooth workings of important applications.
It is reasonably well known that the combination of gold’s physical and chemical characteristics make it the metal of choice for a number of high-specification procedures. It is the metal with the third highest electrical conductivity behind silver and copper and although it is considerably more expensive than either, its very high corrosion resistance makes it essential for high-performance applications, notably electronic bonding wire and gold plated connectors and it has been invaluable in uses on outer space.
The key area is the electronics sector, which consistently accounts for more than 200 tonnes per annum of demand, although dental fillings are probably higher in the public consciousness (and account for a consistent 65-70 tonnes per annum), along with decorative purposes such as gold leaf. The value of gold that went into industrial uses in 2004 was US$5.4 billion, against $4.6 billion for platinum, $3.7 billion for silver and $1.4 billion for palladium. Much of this usage is not recycled because the metal is so widely dispersed and in tiny quantities for each component. There is, however the possibility of an increase in recycled gold from electronic components after the EU WEEE (Waste Electrical and Electronic Equipment) directive is implemented, forcing manufacturers to recycle components at the end of their useful life – although two-thirds of electrical goods actually fall outside this Directive by virtue of exemptions.
Future uses capture the imagination and revolve in part although by no means exclusively around medical treatment, including the potential use of gold in the treatment of cancer as a result of nanotechnology in which particles can be produced that are a billionth of a metre in length and which has opened up a whole new world of potential. This may not add much tonnage to the gold market, but it could certainly improve our prospects for healthcare.
The development of nanotechnology has also given gold an important role in catalysis, something that was dismissed by the chemical industry as recently as 30 years ago.
Gold is inert inside the body and has a rapidly increasing number of uses. An important use is in gold plated stents, which are used in the treatment of heart disease (opening up the arteries), in ear implants, in the use of anti-arthritis drugs and as a delivery mechanism for drugs to specific parts of the body. It is in this latter that it is under development for cancer treatment. Gold colloidal nanoparticles bind easily to drugs and a process is under development that will allow the gold to carry the drugs safely through the blood stream. The drug is targeted directly at the tumour and the gold particles then selectively accumulate in and around the tumour due to the inherent leakiness of new blood vessel within the tumour.
This sidesteps the multi-drug resistance that some tumours have developed and avoids the debilitating side effects of some existing drugs such as the platinum-based cisplatin. The important thing about this is that the carrying agent has to be gold, because gold of gold’s inertness within the body.
Elsewhere gold is emerging as a potential for controlling mercury pollution from coal-fired power stations (mercury is a leading cause of Alzheimer’s disease).
Gold’s inertness has always led chemists to believe that it would not work as a catalyst, but nanotechnology, changes its characteristics from those of the bulk metal and allows unique properties to be engineered.
There are numerous potential uses here, with the possibility of substituting for the PGMs or silver in some catalysts – gold’s great advantage is that it can substitute for some of these metals in chemical processes and be effective at a much lower temperature than the alternatives. One potential use here, although it will take a lot of item for the development, is the use of gold in emission control catalysts.
Up to 75% of vehicle emissions from the exhaust system take place before “light-off”, which is typically above 300°C and by definition takes place when the engine has just been switched on and is warming up. Subject to legislative and economic parameters, the use of gold in conjunction with the PGMs in this application may well have some potential (gold could not be used on its own as it has some thermal stability problems). This is a long shot, however and given the nature of the industry, is not just a long shot but a long-term long shot.
While we are on the subject of the long term, as Dr. Holliday pointed out, the commercial-scale application of fuel cells has been just around the corner for many years (and to this writer’s certain knowledge since 1983) but at long last it does look as if there is some potential for both stationary and mobile applications. There is scope for the use of gold here also, in the purification of the hydrogen feedstock as well as fuel cell catalysts themselves.
At present the only gold catalyst in commercial use is for the production of vinyl acetate monomer, but there is scope for numerous additional applications in the manufacture of plastics, production of foodstuffs and the processing of petrochemicals, not to mention improving the viewing angles on LCD screens and improving the efficiency of solar cells.
Meanwhile veterinarians at Rome’s zoo last week treated an elderly arthritic lion called Bellamy by injecting 50 gold pellets into his spinal muscles near the joints. Dogs cats and a tiger have all had the treatment before, but this is the first time the King of the Jungle has been so treated – he is believed to be padding about in much less pain than previously.
All space-age technology, one might think – but in 1954 scientists were forecasting that by 2004 a home PC would be a viable product, taking up a wall-space of roughly three metres by two…. |
