While neural implants play a vital role in monitoring or stimulating parts of the brain, they're often attacked by the body's immune system. A new device gets around that problem by being very soft – and it's implanted using a needle made of sugar.
Although some neural implants are now relatively flexible, they're still much stiffer than natural brain tissue. As a result, they poke into that tissue, making their presence known. The body thus sees them as the foreign objects that they are, producing an inflammatory response and covering them with scar tissue. Needless to say, this impedes their function.
Seeking an alternative, scientists at Canada's McGill University created a silicone implant that is approximately the thickness of a thin sewing needle (about 0.2 mm), and which is officially "the softest brain implant to date." It's described as having a consistency similar to that of soft pudding, not unlike the brain itself.
Because the implant is so soft and fragile, though, surgically inserting it could prove difficult. The researchers got around this problem by placing it inside of a needle made of sugar. That sugar was first melted and then molded, finally hardening into the form of the finished needle. Liquid silicone was then injected into a cavity within the needle, forming the implant once it set.
In lab tests, the non-toxic sugar needle was successfully used to guide the implant into target areas of anesthetized rats' brains. Within seconds of reaching those targets, the needle harmlessly dissolved, leaving the implant behind. When the brains were examined three and nine weeks later, the soft implants were found to have produced a much lower foreign body response than traditional harder neural implants.
Future research will focus on equipping the implants with electronics, allowing them to perform actual functions.
"The implants we created are so soft that the body doesn’t see it as a big threat, allowing them to interact with the brain with less interference," says the lead scientist, Edward Zhang. "I am excited about the future of brain implant technology and believe our work helps pave the path for a new generation of soft implants that could make brain implants a more viable medical treatment."
The research is described in a paper that was recently published in the journal Advanced Materials Technologies.
Source: McGill University