neurons growing over magnetic micro-bots
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Credit: Hongsoo Choi

Like LEGOs for your brain, magnetic micro-bots can click damaged neurons back together

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Oct 13, 2020, 12:33 AM EDT (Updated)

If you shoved LEGOs up your nose as a kid, they probably didn’t get anywhere near your brain, though your horrified parents might have still rushed you to the emergency room.

Now there are micro-bots that act like LEGOs for your brain. Neuroscientist Hongsoo Choi and his team of researchers have developed robots that can only be seen under a microscope, but when it comes to connecting a gap in gray matter caused by disease or injury, they have pretty much the same function as a LEGO brick or structure that clicks in place to connect two other structures. They’re just not plastic. These bots are placed in that gap and have tiny grooves that guide brain cells, or neurons, to grow across the empty space and link up with neurons on the other side so they can zap messages to each other.

This is not the type of neural network you may think of when something like Neuralink comes to mind. While Neuralink does have medical functions that could also repair neural pathways, Elon Musk’s ultimate vision for it is to eventually connect the pathways of thought between different individuals. Think of Choi’s bots as connectors that help reconnect neurons whose connections were previously severed. When those neurons grow projections, or neurites, which look like neon tentacles in the photo, those neurites are guided across a magnetically linked structure of micro-bots. They connect with each other again and reactivate their own network. No one is getting linked up to anyone else — just neurons with neurons.

"I think once the neural cells on the microrobot make connections with surrounding neural cells, it might difficult to relocate them with readjustment. However, we can the neural network as we want before the neural cells on the microrobot making connections with surrounding neural cells,” Choi, who led a study recently published in Science Advancestold SYFY WIRE.

Think of it this way. Say LEGO came out with a starship model that involved two wings and a pilot pod in the center. As tempting as it is to think of it as the epic LEGO Millennium Falcon that actually does exist, think of it as more of a TIE Fighter type of structure. If this thing is going to survive without falling apart, the connection between the pod structure and wings needs to be strong on both sides. You also need to read the directions to build it correctly. Otherwise, you’re going to end up extremely frustrated at the chaotic pile of plastic bricks staring back at you. 

Credit: LEGO/Amazon

 

Imagine the neurons on either side of the brain gap as the wings of the starship and the multi-bot structure as the pod between them. Choi and his team conducted lab experiments in which they found that neurons extend neurites randomly without something to guide them. Even bots with a smooth surface showed no results. That was because even the thinking cells of the body don’t know what to do if they are not told not to do. If you lost the instruction manual and tried to figure out the structure of this starship on your own, it would probably keep falling apart until you finally found the manual. It was the grooves that acted as the instruction manual that told the neurons where to go in order to click with those on the other side.

Since Choi's team developed this technology in vitro, outside the body, they will eventually have to prove it can work in vivo, meaning inside a live brain. Human neurons will also have to try it out, since the initial experiments used hippocampal rat neurons. So what does he expect to see when they operate in living tissue and, eventually, a human brain?

"For small animals, we are working on other types of microrobots for drug or cell delivery," he said. "For a human trial, I am not sure how long it will take. It mostly depends on the funding and regulation. I hope our team can continue this research with enough funding."

While Choi's micro-bots not been tested in an actual brain (human or animal) yet, they have the potential to repair broken links that are the result of brain damage caused by injury or diseases such as Parkinson’s or Alzheimer’s in the future. He will only keep leveling up his technology. Because the bots are magnetized, their formations can be manipulated by a magnetic field to be at just the right angle for neurites to spread across and make a connection. They will also continue to be updated for efficiency.

"We can dynamically make neural networks as we want. However, we may need further study to confirm they can be dynamically adjusted. I guess the question is not about the microrobot but the cell viability for adjustment," Choi said. "Also, the microrobot we prototyped in vitro cannot be used in vivo because the used material is not biodegradable. For in vivo use, biocompatible and biodegradable materials should be used."

Say that the LEGO starship’s wings stay connected to the pod well enough until you hang it up and they start to sag. LEGO becomes aware of those faults and releases Starship v2, whose pod structure is built to have stronger connections to the wings. Hang it up and it will appear to soar.

You will probably never look at LEGOs the same way again.

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