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How do you keep a tiny probe in a living brain? One approach is to create an ultra-flexible probe that ‘floats’ in it.
Image: Neuronano Research Center
Your brain never sits still. Even your tiniest movements – such as breathing – make it bob gently in the supportive fluid that bathes it inside your skull.
This makes it challenging to anchor probes in a living brain for long periods. As the brain tissue moves, the delicate probes can become dislodged. Over time, the moving probe can irritate the brain cells. This causes the cells to build up scar tissue around the probe. Once this happens, the probe cannot record any more signals.
Jens Schouenborg’s research group have devised two strategies to overcome this. They will use this kind of probe to accurately record and stimulate brain cell activity.
Jens Schouenborg is Professor of Neurophysiology at Lund University, where he coordinates the Neuronano Research Center.
Floating probes As they are made of metal, these probes are denser than the brain tissue around them. So when the brain tissue moves, the probes will move at a different speed, and with more momentum than the tissue. This irritates the brain tissue.
Jens’s group plan to attach ‘floats’ to these probes, represented as red structures in the picture. This will make the probes less dense, so that they match the density of the brain tissue more closely. As a result, they will move with the brain tissue instead rubbing against it when the patient’s head moves.
Ultra-flexible probes Jens’s group have also created ultra-flexible, multi-tipped probes inspired by seaweed. Notice how they bend and sway gently with the same speed and momentum as the fluid.
Future medical applications for these probes include deep brain stimulation for treating Parkinson’s and Alzheimer’s disease, chronic pain, depression and epilepsy.
These highly accurate probes will allow doctors to target parts of the brain more accurately and minimise the side effects of treatment.
Jens also envisions the probes being used to improve interfaces between brain and machine for bionic devices that restore vision, hearing and movement.
Jens (right) with the Lund University Neuronano Research group.