|Injectable electronic polymer mesh--Courtesy of Lieber Research Group, Harvard University|
Harvard University researchers have developed a soft, conductive electronic polymer mesh that can be injected into the brain to monitor and stimulate it at the level of individual neurons. They have published preclinical data on the device in the latest issue of Nature Nanotechnology.
If it could be tested successfully in humans, the researchers believe that it could be useful in treat stroke or Parkinson's disease patients.
Researchers have thus far implanted mesh consisting of 16 electrical elements into the brains of two mice, which were both used effectively to monitor and stimulate individual neurons. After 5 weeks, the mesh had tightly integrated with the neural cells and the mice showed no signs of an elevated immune response, said a news article in Nature covering the developments.
"Our results show that electronic components can be injected into man-made and biological cavities, as well as dense gels and tissue, with >90% device yield," the researchers, who were led by Harvard chemist Charles Lieber, conclude in the paper.
The mesh was injected via syringe and unfolded to become submicrometer-thick, centimeter-scale macroporous mesh electronics through needles with a diameter as small as 100 micrometers.
The study came out of early work from Lieber's lab examining cardiac and nerve cells grown on embedded scaffolds.
"We were able to demonstrate that we could make this scaffold and culture cells within it, but we didn't really have an idea how to insert that into pre-existing tissue," Lieber said in a statement. "But if you want to study the brain or develop the tools to explore the brain-machine interface, you need to stick something into the body."
He continued, "When releasing the electronics scaffold completely from the fabrication substrate, we noticed that it was almost invisible and very flexible like a polymer and could literally be sucked into a glass needle or pipette. From there, we simply asked, would it be possible to deliver the mesh electronics by syringe needle injection, a process common to delivery of many species in biology and medicine--you could go to the doctor and you inject this and you're wired up."
The injectable syringe delivers the electronic mesh via a rigid shell. Researchers expect that a large volume of the flexible electronics could be injected alone or in conjunction with other materials.
"I think it's great, a very creative new approach to the problem of recording from large number of neurons in the brain," Rafael Yuste, director of the Neurotechnology Center at Columbia University in New York, NY, who was not involved in the work, told Nature.
"I do feel that this has the potential to be revolutionary," Lieber added. "This opens up a completely new frontier where we can explore the interface between electronic structures and biology. For the past thirty years, people have made incremental improvements in micro-fabrication techniques that have allowed us to make rigid probes smaller and smaller, but no one has addressed this issue--the electronics/cellular interface--at the level at which biology works."