Diamonds to shed light on signals in the brain
By Anne Kirsten Frederiksen
New quantum technological methods are to enable exploring what happens when a brain signal moves from A to B. This knowledge is essential to understanding the dynamics of the brain.
New quantum technology makes it possible to measure much finer and less magnetic signals in human tissue than previously.
The explanation lies in a small diamond sensor—an artificially produced diamond with a built-in defect which enables utilization of one of the basic elements of quantum physics: superpositions. Superposition means that a particle may be in two different states at the same time; the direction of an electron spin can, for example, be both up and down at the same time. Measurements can thereby be made at atomic level in human tissue with previously unseen accuracy.
“Today, we can measure activity, for instance from the heart, by means of electrical signals. This is done using ECG, for example, where we measure signals from the various places in the body where the electrodes are attached. But we don’t know what happens on the way between two electrodes, such as between the heart and the foot. We can measure that with magnetic fields which are not disrupted when encountering tissue, blood, and bones in the same way as electrical signals,” explains Associate Professor Alexander Huck, DTU Physics.
Electrons facing both up and down at the same time
The magnetic fields are measured by means of a quantum technological method that is based on the fact that the diamond sensor’s electrons may be in both spin-up and spin-down states at the same time. Just like a spinning top, the spin direction of the electrons will also carry out a periodic precession—‘wobble’—and the frequency of the movement is sensitive to magnetic fields. It is this coupling which enables measuring magnetic fields in human tissue by means of diamond sensors. In addition, the electrons form part of an electron spin that is subject to periodic changes, just like we know it from the Earth which spins around itself while shifting its axis. This spin is sensitive to magnetic fields in its surroundings, which makes it possible to measure the magnetic fields in human tissue.
“It will be essential—particularly in relation to brain signals—to gain an insight into what happens as the signal moves from one place to another. Once we have this information, it will also be possible to develop medications which either stimulate or block the signals in the brain and thus contribute to attenuating or completely eliminating the symptoms of brain-related diseases such as Alzheimer’s.”
Great impact on medical treatment
In collaboration with Hvidovre Hospital and the University of Copenhagen, Alexander Huck and his team of researchers are currently making the first attempts at measuring brain activity with diamond sensors. This is done through measurements in the neural pathways on a brain slice from a rat.
“These are complicated experiments, as we can only keep the brain alive for a couple of hours. Moreover, we need to make sure that the signals we measure are valid and originate from the brain and not from other elements nearby, for example a person walking by with a mobile phone switched on. We therefore need to verify by means of control measurements using other methods, for instance electrodes and electrical signals, that our results are valid.”
Alexander Huck points out that there are many advantages of performing measurements with diamond sensors. Firstly, the sensor, which does not have the shape of a diamond but closely resembles a small 2 x 2 mm glass plate, is very robust. Secondly, the diamonds are in no way dangerous or toxic and therefore do not affect human tissue when used for measurements.
The partner: Hvidovre Hospital is also satisfied.
“I work with MR scanning on a daily basis, and I’m very impressed with the results that have been achieved so quickly. Many other methods for measuring brain activity are limited by the fact that we see a few aspects only—but the diamond sensor enables us to see all neurons at the same time; it’s like watching a film of the brain activity in extremely high resolution,” says Senior Researcher Axel Thielscher, who is an associate professor at DTU Electrical Engineering and a senior researcher at Hvidovre Hospital.
First use will be in cancer treatment
“We still have some way to go before we can publish the first results of measurements in the brain. But we’ll be able to use the technique in cancer treatment already in the course of the next couple of years. Diamond sensors are able to differentiate between individual cells and thereby ascertain whether all cancer cells in a treated area have been killed, or whether there are still living cancer cells left which can spread to the rest of the body. This will be the first huge step with the new diamond sensor technique, and a bit further down the road it will also have a decisive impact on the efforts to combat brain diseases like, for example, Alzheimer’s,” says Alexander Huck.
The hope is not just to contribute significant measurements for use in the healthcare sector, but that other sectors will also be able to see an advantage in using the new technology and its ability to perform very precise measurements on a very small scale.
“Interested parties are always welcome to contact us to talk about the opportunities that measurements with diamond sensors offer,” concludes Alexander Huck.
The research programme is financed by Innovation Fund Denmark and coordinated by Professor Ulrik Lund Andersen, DTU Physics.
source: Technical University of Denmark