See-Through Sensors Open New Window Into The Brain

A blue light shines through a clear implantable medical sensor
 onto a brain model. See-through sensors, which have been
developed by a team of University of Wisconsin Madison
 engineers, should help neural researchers better view brain
activity. (Credit: Justin Williams research group)
Developing invisible implantable medical sensor arrays, a team of engineers has overcome a major technological hurdle in researchers' efforts to understand the brain. The team described its technology, which has applications in fields ranging from neuroscience to cardiac care and even contact lenses, in the journal Nature Communications.
Neural researchers study, monitor or stimulate the brain using imaging techniques in conjunction with implantable sensors that allow them to continuously capture and associate fleeting brain signals with the brain activity they can see. However, it's difficult to see brain activity when there are sensors blocking the view.
The researchers chose graphene, a material gaining wider use in everything from solar cells to electronics, because of its versatility and biocompatibility. And in fact, they can make their sensors incredibly flexible and transparent because the electronic circuit elements are only 4 atoms thick, an astounding thinness made possible by graphene's excellent conductive properties.
The transparent sensors could be a boon to neuromodulation therapies, which physicians increasingly are using to control symptoms, restore function, and relieve pain in patients with diseases or disorders such as hypertension, epilepsy, Parkinson's disease, or others.
Currently, the researchers are limited in their ability to directly observe how the body generates electrical signals, as well as how it reacts to externally generated electrical signals. Clear electrodes in combination with recent technological advances in optogenetics and optical voltage probes will enable researchers to isolate those biological mechanisms. This fundamental knowledge could be catalytic in dramatically improving existing neuromodulation therapies and identifying new therapies.
While the team centered its efforts on neural research, they already have started to explore other medical device applications. For example, working with researchers at the University of Illinois-Chicago, they prototyped a contact lens instrumented with dozens of invisible sensors to detect injury to the retina; the UIC team is exploring applications such as early diagnosis of glaucoma.