The neuroscience field has witnessed new discoveries in the past decades because of the use of electrodes implanted inside the brains lab specimens. Common silicon-based electrodes are based on established manufacturing techniques, but are stiff and prone to causing injury to the brain. These problems are avoided with more flexible polymer-based electrodes, however, they are not easy to scale up, particularly when incorporating light emitters for stimulation of the brain.
Lawrence Berkeley National Laboratory researchers created a method to assemble optoelectrodes. It seems to offer the best of both. The scientists showed that it is possible to create semi-flexible light emitting devices by removing the silicon material underneath the probe’s edge.
The optoelectrode is a tool that can be used to study the deep brain tissues. It can capture signals from individual nerve cell and stimulate small groups of neurons with state-of-the art techniques like optical waveguides.
Vittorino Lanzio, the writer, said that although it is difficult to implant probes made of polymer in the brain, he and his colleagues have developed a simple fabrication technique. They are much easier to insert since they don’t have to be fixed to the silicon shuttle or the tungsten shuttle. This increases the footprint of the device during its inserting.
Optoelectrodes can be used only in short-term studies on laboratory animals. Although the new electrode is an important step towards better biocompatibility, more needs to be developed in order to bring long-term electrode use to humans.
The minute breathing patterns and pulses of blood flow subtly joggle the brain, even at rest. Small changes in microscopically tiny amounts can cause brain structures to become damaged or destroyed. These injuries could trigger immune cells that hamper the function of electrodes.
The brain’s consistency is even more fragile than jelly.
Stefano Cabrini, Author
The optoelectrode is made of oxide glass and nitride initially joined to silicon. To remove silicon from the device’s insertion area the group employs a nanoscale etching technique.
The team has tested the device using experiments on rats and found that the semiflexible device, which packs 64 electrodes and high-density photonics into smaller cross-sectional areas, could be inserted into a brain without using an tungsten or silicon shuttle.
The researchers hope neuroscientists apply the new device to use and incorporate more functions into the electrodes, such as microfluidics to inject chemicals into the brain, as the field progresses.
Lanzio V., and Lanzio V., and. (2021). Neural optoelectrodes combining polymeric-like bendability and semiconductor scalability to low damage acute in vivo neural stimulation and readouts. Journal of Vacuum Science & Technology B. doi.org/10.1116/6.0001269.
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