Researchers at the University of Southern California Viterbi School of Engineering have developed thin, flexible polymer-based materials for use in microelectrode arrays that record activity more deeply in the brain.
Each microelectrode array is made up of eight ‘tines’, each with eight microelectrodes that can record from a total 64 sub regions of the brain at once.
The polymer-based material, Parylene C, is said to be less invasive and damaging to surrounding cells and tissue than previous microelectrode arrays comprised of silicon or microwires.
However, the long and thin probes can easily buckle upon insertion, making it necessary to add a self-dissolving brace made up of polyethylene glycol (PEG) that shortens the array and prevents it from bending.
"The information that we can get out is equivalent, but the damage is much less," said Professor Ellis Meng of the USC Viterbi Department of Biomedical Engineering and Michelson Center for Convergent Bioscience. "Polymers are gentler on the brain, and because of that, these devices get recordings of neuronal communication over long periods of time."
Researchers say as with any prosthetic implant, caution must be exercised in terms of the body's natural immune response to a foreign element.
However, Parylene C, which is biocompatible, can be micro-fabricated in extremely thin form that moulds well to specific sub-regions of the brain, allowing for exploration with minimal tissue displacement and cell damage.
Future research will determine the recording lifetime of polymer-based arrays and its long-term "signal-to-noise" (SNR) stability.
The team plans to create devices with higher density, including a double-sided microelectrode array with 64 electrodes per tine instead of eight, making for a total of around 4,000 electrodes placed in the brain at once.