Colloidal gold, the suspension of gold nanoparticles in liquid, has been used for hundreds of years, from staining glass in the Middle Ages to early experiments with photography in the Victorian era. But it was only 160 years ago that gold nanoparticles were given any serious scientific examination when scientist Michael Faraday created the first pure sample of colloidal gold in his basement laboratory at the Royal Institute in London. Faraday’s early experiments were forays into what would ultimately become the fields of nanoscience and nanotechnology.
Despite many decades of technological development since then, the healthcare potential of gold nanoparticles is only coming into focus now. This largely reflects recent developments which have allowed scientists to synthesise gold nanoparticles of various shapes and sizes, consistently and at scale. These nanoparticles are also stable, easily functionalised and, critically, biocompatible, meaning they can potentially be used in the body as therapeutic agents.
In combination, these properties mean that gold nanoparticle-based technologies have enormous potential in the healthcare sector. We are already seeing a wide range of possible applications in diagnostic testing, medical treatments, and procedures, such as drug delivery, gene therapy, tumour detection and radiotherapy dose enhancement. Innovative applications for gold nanoparticles regularly make headlines in scientific journals and the mainstream press too.
Polish scientists, for example, recently patented a formula for artificial saliva that includes gold nanoparticles. The saliva will help patients who have salivary secretion disorder, a condition that means they are unable to swallow, eat and speak. Professor Halina Car from the Medical University of Bialystok said the formula combines at least four properties of natural saliva, while improving lubricity, boosting anti-microbial properties and maintaining hygiene by preventing dental plaque development.
In the US, scientists from the University of Missouri have developed a method of cross-linking gold nanoparticles with collagen gels to treat ageing or damaged skin. Collagen gels are used as soft tissue fillers, to reconstruct soft tissue that has been damaged as a result of age, disease or trauma. The gold nanoparticles, which exhibit high surface reactivity, antioxidant and antimicrobial behaviours, are used to improve the collagen’s resistance to degradation.
And in Switzerland, scientists have pioneered a revolutionary approach in the use of gold nanoparticles that could lead to the development of a new generation of broad-spectrum antiviral drugs. Researchers at the Ecole Polytechnique Federale de Lausanne (EPFL) in Switzerland created gold nanoparticles that can attract viruses and destroy them. When injected into the body the nanoparticles mimic human cells and ‘trick’ the viruses into binding with them to infect them. This deforms the viruses and opens them, rendering them harmless. Broad- spectrum antiviral drugs have the potential to cure many deadly viruses that are currently untreatable, from HIV to Ebola. They could also help curb the rise of antimicrobial resistance arising from the over-use of antibiotics.
Scientists have pioneered a revolutionary approach in the use of gold nanoparticles that could lead to the development of a new generation of broad-spectrum antiviral drugs.
I have focused my professional attention on gold nanoparticle technology for years, working with lateral flow assays in particular. These are relatively simple devices, used to detect diseases or other conditions outside of a laboratory setting, home pregnancy kits or cost-effective, reliable tests for diseases including malaria and HIV/AIDS.
Now, at Sona Nanotech, we have created a unique gold nanoparticle product, synthesising high volumes of high- quality rod-shaped gold nanoparticles without the use of the toxic chemical cetyltrimethylammonium bromide (CTAB). Ideally suited for diagnostic testing, our gold nanorods are the first in the world to be created without CTAB, which means they can be used inside the body.
They have the potential therefore to be enabling technologies for such medical innovations as the non-invasive targeted cell, tumour, tissue and organ treatments including photothermal cancer cell destruction and location-specific drug and pain treatment.
Analysts predict that the global, gold nanoparticles market will grow at a compound annual growth rate of 18.84% between 2017 and 2021, driven largely by increasing demand for medical applications.
Having travelled extensively over the last few months, discussing this breakthrough and identifying new partners and opportunities, I have experienced first-hand the growing demand for innovative gold nanoparticle products. China, in particular, is a vast untapped market with the healthcare industry being especially focused on lateral flow diagnostic testing products, specifically those targeting heart disease. The country has more than a quarter of the worldwide market for these products but local manufacturers often make gold nanoparticles in-house and quality control is poor. This leads to a sub-optimal final diagnostic product so firms are moving to other methods of clinical diagnostic testing, using markers such as fluorescent markers and quantum dots. While these methods are new and innovative, they are more expensive than gold and don’t necessarily produce better results.
Looking ahead, there is an enormous opportunity for lateral flow diagnostic manufacturers in China to create better quality, stable gold nanoparticles, which can be reliably produced at scale. It is not a complex issue and it would help to drive the availability of high-quality, cost-effective healthcare solutions around the world, and Sona is committed to making this happen.
For those of us working in the field, it is exciting to see the technological innovations and breakthroughs involving gold nanoparticles – and the business and investment opportunities that stem from them. Indeed, analysts predict that the global, gold nanoparticles market will grow at a compound annual growth rate of 18.84% between 2017 and 2021, driven largely by increasing demand for medical applications from home or point-of-care testing to drug delivery in cancer treatment. While the quantities of gold used in these types of application are small, the added value and impact to individuals are potentially very significant. This branch of science and technology has much to offer in the twenty-first century and beyond.
A version of this article was originally published in Gold Investor magazine