Researchers have developed microscopic, wireless bioelectronics that circulate through the blood and self-implant in a target region of the brain to provide focused treatment.
In a study on mice, researchers demonstrated that after injection, these minuscule implants can identify and travel to a specific brain region without requiring human guidance.
Once there, they can be wirelessly powered to provide electrical stimulation to the precise area.
Such stimulation – neuromodulation – has shown promise as a treatment for brain tumours and diseases, such as Alzheimer’s and multiple sclerosis.
And because the electronic devices are integrated with living, biological cells before being injected, they are not attacked by the body’s immune system. They can cross the blood-brain barrier while leaving it intact.
The researchers have named the technology ‘circulatronics’, with implants that can provide localised neuromodulation deep inside the brain, achieving high precision, to within several microns around the target area.
Additionally, the biocompatible implants do not harm surrounding neurons.
Deblina Sarkar is the AT&T Career Development Associate Professor in the MIT Media Lab and MIT Centre for Neurobiological Engineering, head of the Nano-Cybernetic Biotrek Lab, and senior author of a study on the work.
She believes that circulatronics technology holds the potential to make therapeutic brain implants accessible to all by eliminating the need for surgery.
She is joined on the paper by lead author Shubham Yadav, an MIT graduate student; as well as others at MIT, Wellesley College, and Harvard University. The research has been published in Nature Biotechnology.
The team has been working on circulatronics for more than six years. The electronic devices, each about one-billionth the length of a grain of rice, are composed of organic semiconducting polymer layers sandwiched between metallic layers to create an electronic heterostructure.
They are fabricated using CMOS-compatible processes in the MIT.nano facilities, and then integrated with living cells to create cell-electronics hybrids. To do this, the researchers lift the devices off the silicon wafer on which they are fabricated, so they are free-floating in a solution.
Key to their operation is the high wireless power conversion efficiency of the tiny electronics. This enables the devices to operate deep inside the brain while still harnessing sufficient energy for neuromodulation.
The researchers use a chemical reaction to bond the electronic devices to cells. In the new study, they fused the electronics with a type of immune cell called monocytes, which target areas of inflammation in the body. They also applied a fluorescent dye, allowing them to trace the devices as they crossed the intact blood-brain barrier and self-implanted in the target brain region.
While exploring brain inflammation in this study, the researchers hope to utilise different cell types and engineer them to target specific regions of the brain.
The Sarkar lab is currently working on developing their technology to treat multiple diseases, including brain cancer, Alzheimer’s disease and chronic pain.
The researchers hope to move the technology into clinical trials within three years through the recently launched start-up Cahira Technologies.
They are also exploring the integration of additional nanoelectronic circuits into their devices to enable functionalities such as sensing, feedback-based on-chip data analysis, and capabilities like creating synthetic electronic neurons.
