A new electronic device can be directly injected into the brain and other parts of the body to treat debilitating conditions such as neurodegenerative disease and paralysis.
The researchers created nano-scale electronic scaffolds that resemble tiny nets, and can be injected via syringe, Harvard University reported. Once they are connected to the electronic devices, the mesh can be used to monitor neural activity, stimulate tissue, and even trigger the regeneration of neurons.
"I do feel that this has the potential to be revolutionary," said Charles Lieber, the Mark Hyman, Jr. Professor of Chemistry. "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."
I past studies, the researchers demonstrated the scaffolds could create "cyborg" tissue, which are cardiac or nerve cells grown using the medical nets. The devices also recorded the electrical signals generated by the tissues, and the changes that occurred after drugs were administered.
"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. "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. 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.'"
These nets could be used to treat a wide variety of disorders, and are surprisingly easy to manufacture despite their complexity. The process is similar to what is used to create etch microchips, starting out with a dissolvable layer which is deposited on a substrate. Researchers then lay out a mesh of nanowires and layers of organic polymer, the first layer of which dissolves to create mesh flexible enough to be drawn into a syringe needle.
"Existing techniques are crude relative to the way the brain is wired," Lieber said. "Whether it's a silicon probe or flexible polymers...they cause inflammation in the tissue that requires periodically changing the position or the stimulation. But with our injectable electronics, it's as if it's not there at all. They are one million times more flexible than any state-of-the-art flexible electronics and have subcellular feature sizes. They're what I call "neuro-philic" - they actually like to interact with neurons.."
After it is injected, the mesh can be connected to conventional medical measurement electronics to keep a close eye on neural activity. In the future, the researchers hope to gain insight into how the brain and other body tissues react to the injectable electronic over a long period of time.
"Having those results can prove that this is really a viable technology," Lieber said. "The idea of being able to precisely position and record from very specific areas, or even from specific neurons over an extended period of time - this could, I think, make a huge impact on neuroscience."
The findings were published in a recent edition of the journal Nature Nanotechnology.
