Gold’s Role in Fighting Disease

Jewellery, bars and coins: these tend to be gold’s best-known uses. But the precious metal also plays a vital role in medicine, diagnostic testing kits and new nanotechnologies which are being trialled to tackle cancer.

In medicine, gold is being increasingly used in its smallest form -- a nanoparticle -- measuring just 1 to 100 nanometers, or 1 million times smaller than a grain of sand. These tiny particles of gold possess a unique blend of properties. They are stable, compatible with other substances, non-toxic and easily functionalised, making them the ideal tool for a range of healthcare applications. The best-known use of gold nanoparticles is in Lateral Flow Assays (LFAs) which, for many people, have become part of daily life in fighting coronavirus. The same technology is also commonly used to identify Ebola, malaria, norovirus and HIV among others, playing a crucial role in slowing the rate of spread of these diseases.

Gold nanoparticles are also being used in the fight against cancer with medical device company Nanospectra’s AuroLase Therapy, which uses a technique called thermal ablation to heat and destroy tumours. The nanoparticles have ‘optical tunability’, which allows them to convert light into heat and selectively blast the cancer, not the healthy tissue around them.

Nanoparticle technology is also being investigated as a way of stopping the growth of tumours. Biotech firm Qualigen’s QN-247 drug candidate binds a DNA molecule with a gold nanoparticle and the precious metal has been shown to improve the potency of the drug in inhibiting tumour development. It may also increase the drug’s versatility, enabling a wider variety of options to tackle cancerous cells.

Another company, Emergex Vaccines, has created a new type of vaccine using a gold nanoparticle carrier system to inoculate against deadly diseases most prevalent in developing nations. Known as a T-cell priming vaccine, it’s being developed to protect against diseases including Ebola, Dengue fever, Zika and pandemic flu. This technology offers the potential to provide faster, broader and longer lasting immunity to reduce serious illness associated with infectious diseases.

While gold’s use as a nanoparticle is relatively new, the metal has been used in medicine for decades. It’s a key component of auranofin, a small molecule drug that incorporates an atom of gold in its chemical structure that was approved by the U.S. Food and Drug Administration for treating rheumatoid arthritis back in 1985. While the drug remains available as a treatment today, auranofin has been superseded by newer treatments such as methotrexate and hydroxychloroquine, which have proven more effective for arthritis.

However, this may not be the end of the road for auranofin. The drug is at the centre of cutting-edge trials to treat some of the toughest diseases such as ovarian cancer and HIV with the US National Library of Medicine currently listing 14 studies for auranofin across the globe. By “repurposing” a drug that has already gained FDA approval, it can reduce the length and cost of research and trial phases, making it more affordable and achievable than discovering a brand-new drug, with patients gaining access to new therapies more quickly.

This is particularly important for certain neglected diseases common in low- and middle-income countries around the world. One auranofin trial is ongoing in Bangladesh where its potential as a cost-effective treatment for dysentery is being studied. This is currently of significant interest as dysentery is a diarrheal disease that contributes to the deaths of millions of people, particularly young children, in the developing world annually.

Gold’s unique properties, particularly in nanoparticulate form, has placed it at the forefront of developing the next generation of medicines and diagnostics designed to fight some of the world’s most challenging diseases. The power such a tiny amount of gold possesses is quite extraordinary.

Credit: Reuters Plus