Test measures electrolytes from succinic acid
On Winnie E. Svendsen's workbench are 20 of the electronic circuits that each of the new tests will consist of. The circuits are shaped like small chips, where the researchers have used a laser to burn a track in a polyimide film, which is a special type of plastic with very high strength and is used in both spacecraft and small electronic devices.
The laser-fired track creates an electrically conductive pattern of carbon graphene, which has free electrons that can move through the lattice and conduct electricity. By applying a patented layer of nanostructures to the pattern, the burnt pattern can release electrolytes from the succinic acid in the blood sample, creating a current that can be measured and read. This gives the doctor an answer that can determine what treatment the patient should receive.
Results ready in 10 seconds
The specialty of the test lies in the layers applied to the electronic circuit that react to succinic acid. The layers are nano-sized, larger than single atoms, but still very small compared to particles we can see with the naked eye.
The nanostructures have the quality of expanding the sensor surface in the test because the blood droplet doesn't just slide across a flat surface but is instead sent up and down a much larger surface of nanostructures that rise vertically on the sensor surface. This is why doctors can get the crucial answer so quickly. Otherwise, the test could not be used on critically ill patients who are balancing between life and death in crucial minutes.
In addition, a test based on nanostructures is more robust than other types of sensors, such as those based on enzymes, which was the researchers' original idea for a rapid test.
Enzymes are more sensitive to work with because they need to be applied as an extra layer on the chip and are therefore more time-consuming to produce.
‘The best results occur when the blood sample encounters a molecule that can act as a chemical catalyst to release the electrolytes from the organic succinic acid. That's why we were so excited when we succeeded in getting succinic acid to react with the nanostructures,’ says Winnie E. Svendsen.
The goal is for the test to deliver an answer within 10 seconds. The research group at DTU will spend the next two years designing the test kit, which will consist of a chip on which a patient's blood drop is dripped and a reader that the doctor inserts the chip into and reads a number. The researchers are also testing a solution where the test result is transmitted from the reader via Bluetooth so that the result can be viewed on a mobile phone.
Once the test has been validated and approved for a clinical trial, it will be tested in a trial with 200 patients at Herlev, Bispebjerg and Nordsjællands Hospitals who will be randomised to receive either beta blockers or placebo.
Professor Winnie E. Svendsen from DTU Bioengineering heads the research group that has developed the concept for the new rapid test. The official title of the study is COMBAT-TOX, Combat TOXic Catecholamine Syndrome Induced Mortality. The study is supported with DKK 11 million from Innovation Fund Denmark's Grand Solutions programme.
