Colour and chemistry have always combined quite closely for me. When I went to university, I was uncertain what sort of science I wanted to do, but in second year I started to learn about the transition metals that give us a whole realm of beautifully coloured compounds. That led me to being an inorganic chemist, interested in metals. And I guess it informs the fact that I’m now trying to make a colour-based sensor to detect PFAS – per- and polyfluoroalkyl substances.
Chemistry is how I understand the world. But chemistry has been a bit of a double-edged sword: we have remarkable technologies, sure, but they often have consequences that we’re not aware of upfront, and can lead to contamination.
Everywhere we go in the world, we find contamination. But by understanding what is out there and how it can affect us, we can make better choices about how and where we live our lives. The goal with my PFAS work is to create a simple colour-change test that everyday folk can use.
Per- and polyfluoroalkyl substances are a range of molecules that have unique properties: they can resist water, but they can also resist oils to a certain extent. So this makes them really useful on surfaces. They’re in fabrics to stop stains, waterproofing treatments on outdoor clothing, fry pan coatings to stop food sticking, in cosmetics, and they used to be on pizza boxes and microwave popcorn bags.
Chemistry has been a bit of a double-edged sword: we have remarkable technologies, sure, but they often have consequences that we’re not aware of upfront, and can lead to contamination.
But one of the bigger uses is in so-called aqueous fire-fighting foams, or AFFFs. These are the big foam suppression systems used in aviation fires, or industrial fires, where pumping out lots of foams helps put out fires very efficiently.
The problem is that these fire-fighting training grounds or fire sites have had a heap of these PFAS molecules dumped onto the ground, where they can move through the landscape and into the water table. The wonderful chemical properties that allow PFAS to do what they do is based on the carbon-fluorine bonds, but there aren’t natural pathways for those molecules to be broken down, so this leads to these molecules being very persistent in the environment.
This way they can come into contact with people through either their food or water supply. The full health impacts of these PFAS are not known – there’s a lot of work to be done around the consequences of PFAS exposure. But we do know that they accumulate in people, and there are about six health conditions (so far) that have been identified as having firm links with PFAS exposure.
Fire-fighting training grounds or fire sites have had a heap of these PFAS molecules dumped onto the ground, where they can move through the landscape and into the water table.
Simply put, you don’t want your children playing in soil that was once drenched in PFAS, you don’t want to grow vegetables there, and you don’t want to drink contaminated water. But how can you tell if an area or water supply has been affected?
The normal way of testing for these substances involves around half a million dollars’ worth of equipment, usually liquid chromatography-mass spectrometry, which is probably located in a lab that’s hundreds of kilometres away from the actual site of contamination. It’s very expensive and very costly in time to run these tests.
We want to create a simple PFAS test that anyone can use. The basis of our colour-change idea is that we have built a molecule, which is like a little basket for the most common PFAS. And when the PFAS enters the basket, it changes the chemical properties of the basket, which leads to a change in colour. The two molecules can interact with each other without actually undergoing a chemical reaction that sticks them together. This is often referred to as “host-guest” chemistry, where the “host” molecule is the thing that we’ve made, and the “guest” is the PFAS.
The full health impacts of these PFAS are not known – there’s a lot of work to be done around the consequences of PFAS exposure.
We’ve been able to demonstrate this change in colour in laboratory testing, and we’ve protected the work that we’re doing with a patent. The “next big thing” is taking that scientific concept and laboratory activity and transitioning it into a product – something that can be used for a particular problem case, testing soil, say, or water, or perhaps blood.
The big challenge now is linking the fundamental science that we have and pairing up with companies to develop it into something that could be useful in the field.
People are interested, definitely. I’ve had conversations with government agencies and a number of companies. We’re looking to build those networks and understand the gaps where we can most readily apply this technology to real-world problems.
It’s an interesting pathway – and it’s very new territory for me to navigate, as I’ve come from a pure research background. But it’s encouraging to be having these conversations and navigating our way forward so we can more rapidly understand our exposure to these all-too common pollutants.
As told to Graem Sims for Cosmos Weekly.