3D printed at the nanoscale, the ultra-high-density microelectrode array (MEA) is fully customisable, so patients suffering from epilepsy or limb function loss due to stroke could one day have personalised medical treatment optimised for their individual needs.
The team – including Rahul Panat, associate professor of mechanical engineering, and Eric Yttri, assistant professor of biological sciences - applied Aerosol Jet 3D printing to produce arrays that solved the major design barriers of other brain computer interface (BCI) arrays. The team’s findings have been published in Science Advances.
“Aerosol Jet 3D printing offered three major advantages,” Panat said in a statement. “Users are able to customise their MEAs to fit particular needs; the MEAs can work in three dimensions in the brain; and the density of the MEA is increased and therefore more robust.”
MEA-based BCIs connect neurons in the brain with external electronics to monitor or stimulate brain activity. They are often used in neuroprosthetic devices, artificial limbs, and visual implants to transport information from the brain to extremities that have lost functionality. BCIs also have potential applications in treating epilepsy, depression, and obsessive-compulsive disorder, but existing devices have limitations.
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There are two types of popular BCI devices - the Utah array and Michigan array – but they only record on a two-dimensional plane and cannot be customised to fit the needs of each patient or application.
According to CMU, the most important aspect of an MEA is its three-dimensional sampling ability, which is limited by the density of microelectrodes in the array and the ability to position these arrays in a precise area to sense. Modern MEA manufacturing techniques have made advances regarding the density of these microelectrode arrays and adding the third dimension increases the sampling ability of the arrays. In addition, custom-made MEAs for each specific application allows for more accurate and higher-fidelity readings.
The researchers’ CMU Array is claimed to be the densest BCI, about one order of magnitude denser than Utah Array BCIs.
MEAs used for controlling virtual actions on a computer or complex limb movements are running up on limitations of the current technology. More advanced applications require MEAs that are customised to each individual and are much higher fidelity than what is currently available.
“Within a matter of days, we can now produce a precision medicine device tailored to a patient or experimenter’s needs,” said Yttri, co-senior author of the study. In addition, while technologies like visual cortex stimulation and artificial limb control are used successfully by the public, being able to personalise the control system in the brain could pave the way for significant advances in the field.
Panat predicts that it may take five years to see human testing, and even longer to see commercial use. A patent on the CMU Array architecture and manufacturing method is pending.
According to Panat, the next step is to work with the US National Institutes of Health (NIH) and other business partners to get these findings into other labs quickly and apply for funding that would commercialise this technology.
The research is funded by the NIH’s Brain Research Through Advancing Innovation Neurotechnologies (BRAIN) Initiative.
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