A method for manufacturing electronic devices that can be injected directly into the brain could pave the way for advanced treatments for a range of degenerative conditions according to a team of international researchers.
According to a study described in Nature Nanotechnology the group, led by Harvard chemist Prof Charles Lieber, has demonstrated that biocompatible electronic scaffolds can be injected into the human brain and used to monitor neural activity, stimulate tissues and even promote regeneration of neurons.
“This opens up a completely new frontier where we can explore the interface between electronic structures and biology,” said Lieber
The breakthrough builds on earlier work at Lieber’s lab, where cells were cultured within scaffolds that were then used to record electrical signals generated by the tissues.
“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,” said Lieber.
The team realised that when released from the fabrication substrate, the electronics scaffold became invisible and flexible and could be sucked into a glass needle or pipette and injected into the body.
The scaffolds are produced using a process similar to that used to etch microchips.
To create the scaffold, researchers lay out a mesh of nanowires sandwiched in layers of organic polymer. The first layer is then dissolved, leaving the flexible mesh, which can be drawn into a syringe needle and administered like any other injection.
After injection, the input/output of the mesh can be connected to standard measurement electronics so that the integrated devices can be addressed and used to stimulate or record neural activity.
Lieber said that the scale of the scaffolds gives them considerable advantages over other approaches to implanting electronics into the brain.
“Existing techniques are crude relative to the way the brain is wired,” he explained. “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.”