Electronics Shot Monitors Brain

This shot could make you into a cyborg.

Researchers are developing flexible electronics that they can load into a syringe and inject into the body. They envision the mesh of electrodes one day being injected into the brain to “mobilize and monitor neural cells” or into other living tissue to stimulate and record cellular functions.

The Harvard-led international team that is creating the injectable electronics hope it could be used to non-surgically treat paralysis and neurodegenerative diseases. Tests with lab mice have already been able to record brain activity after injection.

“I do feel that this has the potential to be revolutionary,” said Harvard chemist Charles Lieber, who led the study that was published last week in the journal Nature Nanotechnology. “This opens up a completely new frontier where we can explore the interface between electronic structures and biology.”



(Bright-field image showing the mesh electronics being injected through sub-100 micrometer inner diameter glass needle into aqueous solution.

Courtesy of Lieber Research Group/Harvard University.)

In previous work, Lieber’s team developed scaffolds upon which heart and nerve cells could be grown. The electronics could then monitor how these cells responded to drugs. But until this new work, they didn’t know how they’d be able to deliver the scaffolds into living tissue.

“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,” Lieber said. “When releasing the electronic 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?’”



The mesh is made of polymer and platinum metal and, because of its shape, can roll up to fit through the narrow opening of a syringe needle–typically having a diameter of less than 100 microns. Once injected into tissue, it unrolls over the course of an hour to 80 percent of its original shape and loses no electronic functionality. When injected into the brains of lab mice, the electronics elicited little immune response from the host’s systems and reliably monitored brain activity.

“With our injectable electronics, it’s as if it’s not there at all,” he said. “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.”

(Three-dimensional confocal microscopy image of mesh electronics injected into the lateral ventricle, and illustrating the unique integration with and innervation of the neural tissue, as well as the migration of neural progenitor cells on to the mesh within the cavity. Courtesy of Lieber Research Group/Harvard University.)



They say the mesh scaffold could be the interface that biomedical devices currently under development use to directly interact with cells. In future work, the group wants to incorporate multifunctional electronics and wireless connectivity.

Dae-Hyeong Kim and Youngsik Lee, a pair of Seoul National University scientists not involved in the study, say flexible, biocompatible electronics could open up sci-fi therapeutics like fine-detail mapping of brain regions responsible for epilepsy or better treatment for malfunctioning of the heart’s electrical system. In addition, such scaffolds could be the connection point for brain-machine interfaces and spinal-cord-implantable electronics.

The current electronics were built to sense brain activity. Future iterations could detect pH or chemicals.

“The syringe injection of mesh electronics represents a novel strategy for the minimally invasive delivery of soft bioelectronics to deep cavities of biological systems,” Kim and Lee write in an article on the Lieber group’s work. “Further integration of the injectable electronics with other functional units and/or wireless components is expected to lead to promising pathways for innovations in implantable bioelectronics and continuous biomonitoring.”

