Gold in medicine
The biocompatibility of gold has meant that it has been used in medicine for centuries, particularly in dentistry. However in more recent years it has also found as a role in the treatment of disease.
Advances in nanotechnology and a greater understanding of how to manipulate materials at the nano-scale have once again brought gold to the attention of medical researchers. The profession is now identifying ways to exploit gold’s unique properties and build advanced diagnostic devices and treatments.
Watch our 'Gold for heath' video to learn more about the impact such technologies are having on communities around the world.
Gold nanoparticles are at the heart of the hundreds of millions of Rapid Diagnostic Tests (RDTs) that are used globally every year. This well established, and critically important, technology has changed the face of disease diagnosis in the developing world over the last decade.
For example, malaria RDTs work by applying a single drop of blood to a test strip. Gold nanoparticles drive a colour change on the strip if malaria is present. The tests are simple, reliable and robust; they can be used anywhere in the world without the need for expensive equipment or complex supply chains. According to the World Health Organisation (WHO), 155 million malaria RDTs were sold in 2011.
Beyond RDT technology, new, more advanced diagnostic technologies are being developed for specific diseases, applying the unique properties of gold nanoparticles.
HIV/AIDS currently affects around 33 million people worldwide. PointCare, a US-based medical diagnostics company, has brought to market two products, AuRICA and PointCare NOW, which use gold nanoparticles to extend HIV-AIDS patient care and monitoring to the point-of-care in resource-limited settings.
With World Gold Council support, researchers at Imperial College London are also working on improving HIV/AIDS diagnosis technologies. Their experimental gold nanoparticle techniques are able to sense the presence of a target molecule at ultra-low concentration, improving early detection of the disease.
Prostate cancer is the second-most common cancer among men in the United States, and more than 27,000 men die of the disease each year nationally, according to the Prostate Cancer Foundation. The high death toll is partly because the disease has few symptoms in its early stages, meaning that it is difficult to detect.
Existing tests are expensive and inconvenient, but Professor Qun Huo at the University of Central Florida and Dr. Cheryl Baker of M.D. Anderson-Orlando’s Cancer Research Institute are working on engineering gold nanoparticles to attach to cancer-related proteins, making them easier to detect. The World Gold Council supported this research to help to accelerate the commercialisation of this technology.
Gold’s value in medicine worldwide has lasted for millennia, but its use accelerated during the 20th century, with the evolution of modern medicine.
One example is an injectable compound containing gold found to be effective in treating rheumatoid arthritis (RA) after World War Two. It was brought to market in tablet form in 1985, as Auranofin, by pharmaceutical group Smith Kline and French. Although it has been superseded as an RA treatment, a 2012 study showed that Auranofin could be effective in treating diseases that are prevalent in developing countries, such as dysentery. A further study is exploring its potential to treat leukaemia.
In the 21st century, gold nanoparticles are being used extensively in the development of innovative medicines and medical techniques, including ‘needle-less’ vaccine delivery and anti-microbial agents. But perhaps the most promising area of research is in the treatment of cancer.
According to the World Health Organisation (WHO), 7.6 million people died from cancer in 2008, despite advances in diagnosis and treatment. Treating cancer is made more difficult because often the drugs used in chemotherapy can damage healthy cells. Treatments that target cancer cells directly while limiting the impact on the rest of the body could increase the chance of a full recovery. Nanotechnology research is developing more efficient and accurate methods of delivering drugs and other cancer treatments.
CytImmune, a US-based biopharmaceutical company, has developed a method of delivering anti-cancer drugs directly to tumours using gold nanoparticles. The drug is bound to gold particles, which are injected into the bloodstream and travel to the site of the tumour, treating it while leaving surrounding tissue largely unaffected. The technology has gone through its Phase I clinical trials and is undergoing further testing in collaboration with the pharmaceutical company AstraZeneca.
Another company, Nanospectra, has taken a different approach to using gold to treat cancer. The company has created “nanoshells”, consisting of a gold-coated core of silica, which heat up when a laser light of a specific frequency is directed at them. These particles are injected into the tumour, which is then illuminated with a near-infrared laser, destroying the cancer cells with heat.