Mobile mind control: material engineering meets neurobiology
A tiny neural implant, capable of delivering multiple medications and coloured lights and controllable from a smartphone, could speed up research into neuropsychiatric diseases such as addiction and depression. Natalie Healey explores why a meeting of materials engineering and neurobiology might be key to furthering our understanding of the brain.
hen Professor Michael Bruchas, from the University of Washington, is asked about potential malevolent implications of controlling the brain using a smartphone, he lets out a small, good-humoured, sigh. Clearly, he’s heard this question many times before.
“This technology would only be applied to situations where there's a clear psychological need - where the patient would want to be able to control or dampen down unwanted activity in the brain. It’s not going to be used in a sinister way like something out of a dystopian novel,” he reassures.
First, some context. Bruchas is a professor in the Center for the Neurobiology of Addiction, Pain and Emotion at the university in Seattle. He’s dedicated his career to learning more about complex circuits in the brain and how they’re related to various pathologies.
In August, Bruchas and colleagues from South Korea published a paper in the prestigious Nature Biomedical Engineering. The team had invented a device to influence these circuits using a tiny brain implant controlled by an app on a smartphone. This ‘soft neural implant’ is the first wireless brain device able to deliver multiple drugs, the researchers claim. And it could speed up our learning about brain diseases, like Parkinson’s, Alzheimer’s and Obsessive-Compulsive Disorder, by making animal experiments more efficient for scientists.
Untethered access to the brain
Bruchas explains that controlling a laboratory animal’s brain wirelessly allows the team to study behaviour in a more natural way. Wired tech that constrains movement makes it much harder to observe things like stress and pain in mice. And delivering medication to the brain takes a long time.
“Right now, you have to pump drugs into the brain. And it’s very slow and not at the same time that things in the brain are typically working. So it's a practical issue,” says Bruchas.
Not to mention that bulky equipment can cause lesions and scarring in the brain over time, making current methods unsuitable for long-term use. This neural implant, though, is assembled using a soft, super-thin probe, which is about as fine as a human hair. The channels and LEDS within it are smaller than a grain of salt.
“The current technology is probably 50 to 100 years old. It's literally just a metal tube with a plastic tube connected to a pump that you put inside the brain. We thought: ‘this is wild; it's 2019. Can’t we do something a little more technologically advanced?’.”
In praise of international collaborations
Luckily you don’t get more technologically advanced than the research group at the Korea Advanced Institute of Science and Technology. Thanks to their materials engineering knowledge, the device uses Bluetooth low-energy to deliver drugs and light to specific brain cells.
“This evolved from an existing collaboration,” Bruchas reveals. “We felt compelled that there’s a lot of really great materials engineering going on out there, but there’s not a lot of biologists that are accessing that information.”
“We asked: how can we improve on the existing technology’s limitations and shrink it down at the same time and make it wireless and faster? We wanted to mimic the effects in the brain in a more precise manner. That was our goal.”
Controlled by the smartphone interface, the device can trigger a specific combination of drugs, or a precise sequencing of light in the animal’s brain. It allows researchers to set up fully automated animal studies where behaviour of one animal could affect the others around it by conditional triggering of light or medication.
Why light? In the last decade or so, a field called optogenetics has attracted excitement across the scientific community. Using gene therapy, light-sensitive proteins can be expressed in the brain. These are then activated or inhibited when certain wavelengths are delivered there. And chemists across the world are developing pharmaceuticals which would only have an effect when exposed to a particular wavelength. Delivering these drugs to a neural implant like the one the team has developed could mean a future of more precise neuropsychiatric medication, with fewer side effects - something Bruchas is very excited about.
At the moment, the neural device has only been developed with mice in mind, as a research tool for the laboratory. But Bruchas says there’s no reason we shouldn’t design something similar for humans, to be used in a real world setting.
“We do have some ideas about how to make that happen,’ he says. “The irony is that making it work for mice is probably in some ways harder because the device has to be so small. With bigger organisms, it would probably be easier to build.”
And translating the findings to humans might not be too much of a stretch when you consider that brain probes actually exist right now.
“There are about 80,000-100,000 people in the world that have brain stimulators for anything from Parkinson’s to depression to OCD. That’s not an unheard of approach in the brain, particularly for people who don’t respond to medication,” Bruchas points out.
He says his dream scenario is that this research could pave the way for a more precise deep brain stimulator. For instance, when a particular activity in the brain occurs - such as a seizure -, an on-demand release of a drug that only works on that discrete region could occur to module the activity and reduce the troublesome symptoms.
“I don't know if we'll get there. But we're hopeful that we can translate this,” he says. “Deep brain stimulators have been around for more than a generation. They're not controlled by your smartphone, but they're essentially controlled by a little system that’s very similar to what an app would look like. And people use them, and they have them in their brains every day.”
Avoiding the bad guys
For now, based on the rules around current stimulators, Bruchas has faith in our regulatory bodies that the technology won’t get into the wrong hands when it becomes more advanced. We should be optimistic rather than fearful of what engineering and neuroscience will bring in the future. But he believes conversations about regulations and protective mechanisms need to happen now so we’re ready for it when it does arrive.
‘As we move forward in this kind of space, regulatory bodies, neuroethicists, and others are going to have to get together and really decide where the limits of what we use this kind of technology for lie.
“There's always this conversation that scientists do things because we can and not because we should. But neuropsychiatric disease is a huge problem; it takes a huge toll on society,” he concludes.
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