News & blog Pocket Blood Tests: Q&A with Stuart Higgins Written by Alan Barker, Freelance Writer, British Science Festival Diagnosing complex medical conditions can be time-consuming, costly and stressful. Dr Stuart Higgins of the Department of Materials at Imperial College London, is combining advances in physics, engineering and biology to create bioelectronic devices that could make multiple diagnostic tests quick, cheap and easy. Stuart is delivering the Daphne Oram Award Lecture at this year’s British Science Festival. He told Alan Barker more about his work. Stuart will present his research at the British Science Festival Define the problem here. Suppose you go into A&E with chest pain. How does the doctor decide whether you’re having a heart attack or whether it’s something with similar symptoms – perhaps just indigestion? One way is to test your blood for the presence of certain molecules that indicate what’s wrong. The trouble is, for a heart attack you can be looking for several different molecules, which means multiple tests and a long time in A&E before you know what’s wrong. Being able to spot multiple molecules in the blood at the same time not only speeds things up, but can also improve the accuracy of your test. So, instead of measuring just one molecule – The combination of different measurements can be more valuable than just one. You create a kind of mini medical fingerprint, combining the levels of lots of different molecules in the blood. You could compare the fingerprints of people you know have the condition to those without it, to see where a particular person sits in that population. And what bit of the problem are you working on? I’m interested in making these tests easier, cheaper and quicker, so I’m working on a new kind of sensor that will hopefully let me achieve this. The aim is to combine lots of these miniaturised sensors into one small test strip, flow the sample over it and run all the tests at once. So how would you then read off all the different results? Each sensor has an electrical current flowing through it that changes when a molecule sticks to its surface. By measuring how much the current changes, you can work out how much of that molecule was originally in the blood. Being able to spot multiple molecules in the blood could reduce the amount of blood tests taken & improve the accuracy of the test So you’re looking for a way to turn the action of molecules binding to the surface of the sensor into a variation in current? Yes, and a big part of the challenge is making a specific molecule stick to your sensor, otherwise you’ve no idea what you’re measuring. One way is to use antibodies, which are proteins in the blood that bind to specific molecules, normally to flag them up to our immune system. So you’re using different antibodies on top of your sensor to bind different molecules? Yes. There are a number of different proteins produced naturally by the body when it has been injured, including during a heart attack, which have antibodies that will stick to them. Detecting each molecule on its own might not be enough to say for sure what’s happened, as the same protein can be produced in the body under different circumstances. But by looking for a range of proteins at the same time, we can improve how well the test identifies damage to the heart specifically. How does it work? This is where it gets weird. My background is in flexible computer displays – you might have seen recently the announcement of smartphones with bendy screens. I’m borrowing the electrical switches used in these displays (known as transistors), and using them as amplifiers by coating them with antibodies. As specific proteins stick to the antibody (and hence the transistor), there’s a tiny change in electrical charge that the transistor amplifies. Could we be able to use our smart phone to diagnose health conditions? So then you measure all the different changes in electrical current to read off the results? Which means having a device that can measure all those signals. And we all have amazing mini-computers sitting in our pockets, in the form of our smartphones. So the ultimate aim in the future is to develop a disposable test that you could plug into a smartphone via a small reader. Your phone could then measure that mini medical fingerprint. And predict whether you might need help. Exactly: quickly and easily. You could use it at home, with or without a doctor present. We could create disposable tests, using plastic or even paper. Or we could share those measurements privately via the internet to create a medical database, so that you could compare your fingerprint with many others, to help make complex diagnostics more accurate for lots of people. So each test not only helps us individually, but also other people too. Stuart Higgins delivers Pocket Blood Tests at the British Science Festival on Friday 13 September at 13:00. Read more about his lecture and book tickets here.