Of comets and canines: space tech and health

How do you go from space technology - in this case a machine built for Europe's Rosetta mission to analyze Comet 67P - to using that same technology to detect bedbugs in hotels or "sniffing" cancer? 

Well, my background is as an analytical chemist, so I'm used to working in laboratories, building systems to answer a scientific question. And going into space is no different. You have a scientific question. You look at what resources you do and don't have, the budgets you're working with, and while money is not usually an issue in space, it tends to be the size and volume, the mass, the power and energy budget, the temperatures you have to work under, shock and vibration - on a rocket there are really bad vibration and shock loads. And to answer those questions you have to build a multidisciplinary team of people. You can't just have chemists or physicists, you have to have a mixture, including engineers and software engineers. So when you come to look at terrestrial challenges, you're in a good position to look at them from 360 degrees. There are less "unknown unknowns."

What was Ptolemy, the technology you developed for Rosetta's Philae lander?

The Philae lander had a miniature gas chromatograph isotope ratio mass spectrometer. The gas chromatograph is what separates the compounds to allow you to take a complex mixture and separate it into simple compounds. So on the comet it is things like water, carbon monoxide, carbon dioxide, and the organic compounds that are present in the dust - the kind of stuff we're all built from. The mass spectrometer identifies those compounds. And the isotope ratio allows to look not just at the chemistry, but also tells you a little bit about the history of the molecules you're looking at.

We had intended to use it to "fingerprint" the water on the comet. Water on Earth has a measurable ratio of hydrogen and deuterium, it also has a measurable ratio of oxygen isotopes, and we can fingerprint these ratios very accurately. By taking standards on the mass spectrometer to the comet we could compare the fingerprint on Earth to the fingerprint on the comet. Because the idea was whether water on Earth came from this comet? Sadly, due to our landing, we didn’t get a chance to analyse ice core samples and determine these ratios – though ROSINA, on the orbiter, did and they concluded that the signature was not the same. There are a trillion comets though.

But the Rosetta mission is over now. And the problem with space research, though, is that while it sounds exciting, many people don't see how it relates to everyday life on Earth - even if you're looking for the origins of water on our planet. But you've come across an application that does affect people daily, and yet they still might not know it. So tell us how you came to use this equipment to sniff out bedbugs and cancer.

It was serendipity. I took a phone call in a car park and I thought the guy, Jason Littler, was a nutter to start with, because he said to me, "I can smell bed bugs." And I was like, "Okay, really?" But I went away, did my due-diligence, looked it up, and found that you can. And actually the chemicals are quite amenable to the technology we already had, but we did have to make a few changes.

And what about sniffing cancer, in particular prostate cancer?

There was a study by Carolyn Willis in the British Medical Journal in 2004 which used dogs to sniff cancer. It was the first clinical trial that showed statistically that the dogs were not doing it by chance. The dogs were given seven pieces of filter paper onto which the researchers put urine and only one of those [samples] was positive. The dogs were trained to learn the smell for cancer and their performance was better than chance. They should have had a 14 percent chance, but they were much higher.

I then contacted Carolyn. I said I had a machine that could look for chemical signatures, and can we try it. So working with my PhD student, Diane Turner, and Dr Michael Cauchi, who was then at Cranfield University, we were able to develop an assay and an algorithm that did what the dogs did, and that was to look for patterns of compounds above the urine. There are over 970 compounds in the headspace above a urine sample. But it's very complicated. There's no individual biomarker that is either there or not there. What happens is the pattern changes. So you need big computers to develop the algorithms, but once you have them, they can run through a sample and within a few seconds tell whether the patient is positive or negative.     

How soon do you expect to see the technology used in detecting cancer?

We are at least 5 years away from it being used in practice, probably nearer ten. The work on cancer has only been done with a commercial instrument. Once we understand the marker compounds then it is our intention to develop a point of care diagnostic device for a range of diseases, including cancer.  We are at the beginning of the journey. We have the proof-of-principle data to show it has clinical potential. But there is a long road of qualification trials before it ever becomes used in practice. But, as with the Rosetta mission, where we spent 10 years chasing the comet, we are patient people.

Dr Geraint Morgan is with the Department of Physical Sciences at The Open University in the UK. The interview was conducted at the 2017 UK Space Conference in Manchester, UK.