Graphene
is the novel material behind the brain-computer interface (BCI) technology developed by InBrain Neuroelectronics.
In 2020, Barcelona, Spain-based InBrain Neuroelectronics spun out of the Graphene Flagship, an EU research and innovation initiative focused on advancing graphene technology.
InBrain Neuroelectronics secured FDA breakthrough device designation for its system in 2023, with the goal of providing adjunctive therapy for Parkinson’s disease. In September 2024, the device developer launched a first-in-human study, making it the first time graphene has been implanted in a patient’s brain.
“We have a combination of a BCI cortical module [and] a high density subcortical module that come together in a skull-mounted device that actually decodes — in very high resolution — brain networks, and then can stimulate in micrometric resolution as well,” InBrain Neuroelectronics co-founder and CEO Carolina Aguilar said in a Medical Design & Outsourcing interview. “We call this BCI therapeutics (BCI-Tx), the fact that we can read and write — so decode and modulate — in high density and micrometric resolution.”
We asked Aguilar to share some of what she and her team have learned about graphene and its medtech applications. (We’ve lightly edited her responses for clarity and length.)
Graphene’s medtech advantages
Graphene’s “phenomenal” advantages are that it offers micrometric precision for sensing and stimulation, as well as biocompatibility and long-term stability, she said.
The reduced graphene oxide (rGO) that InBrain uses is essentially a stack of flakes, making it a very porous material.
“That porosity also makes the impedance quite low, and therefore the signal to noise ratio very, very high,” she said. “And on top of that, you can induce 200 times more charge density compared to metals. So that is a great advantage in our field, because, you can miniaturize … from 10 micrometers to maybe 1 mm — in our case, so far we use 25 micrometer ‘dots,’ we call them — and that gives you that sensitivity, that resolution, but also that density.”
That graphene contacts spacing as little as millimeters or micrometers yield more precise sensing and energy delivery than metals, where those contacts need at least 1 cm of space between them.
“That precision or that resolution gives you a lot of information of [certain] biomarkers, and understanding those biomarkers allows you to modulate them,” she said. “And on the modulation side, because it’s a non-metal, you don’t have these ferritic reactions that you have in metals, and it becomes a very, very stable material [for] stimulation or modulation. … It’s a critical factor to ensure stability and long-term reliability on the brain of someone for many, many years, 10 or 20 years.”
The technology has “endless applications” beyond neural sensors, including catheter technology and retinal implants.
“It allows you to not only find these biomarkers that sometimes with metals you cannot even see,” Aguilar said. “… Also, to modulate these fibers or these nuclei of the brain at that micrometric precision allows us to get a greater effectiveness, but also reduce side effects, because you are not spreading current around tissues [that] could actually generate different side effects. It is very important to understand which network of the brain you are really targeting and not to cause a lot of other side effects or stimulation in the non-targeted networks or areas.”
Another advantage of working with a material as thin as graphene is conformity. InBrain’s working with thicknesses of 10 to 12 micrometers, which “perfectly adapts to the tissue … like a second skin,” she said, without the stiffness of materials like silicon.
“And then, we have technology that allow us to multiplex so we can get 1,024 contacts with very few wires, which has been one of the one of the challenges in neurotechnology,” she said.
But it’s less about maximizing the number of contacts a device developer can put into a brain and more about the right number and placement of contacts for safe and effective treatment.
“In this field, there is a race to put as many contacts as you want or you think you need,” Aguilar said. “.. But I think it’s not about who can put more contacts on the surface of the brain. It’s more about what those contacts can do clinically in a relevant and meaningful way for the patient. We can not forget about that, because this is not a technology race.”
Medical graphene challenges
The most challenging part of working with graphene is sorting through the various types, configurations and suppliers.
“To make it biocompatible and stable for our application has been the target and the focus,” Aguilar said. “So making sure that the graphene we wanted was in the conditions and specifications we wanted, that it will be absolutely biocompatible, and that on top of that we could keep those properties that make it an ideal BCI interface — that required time. Before InBrain was founded, there were eight years of development for that.”
The Graphene Foundship (founded in 2013) conducted studies on biocompatibility before InBrain launched its preclinical testing for the U.K.’s Medicines and Healthcare products Regulatory Agency (MHRA), the FDA and ISO 13485.
“We got very good results from the very beginning, which reassured us big time,” she said.
Studies on graphene have even looked into the potential risks for people who inhaled graphene oxide nanosheets, including a first-in-human controlled study.
As research continues, graphene will one day become as accepted in medical devices as silicon or platinum-iridium is now, Aguilar said.
“This is something that is a long-term effort, and we will continue,” she said.
