Bioelectronic implants for brain stimulation are used to treat neurological disorders like Parkinson’s disease, epilepsy, and certain mental health disorders. However, they require an invasive surgery to implant.

As an alternative, imagine that clinicians could insert tiny electronic chips into the brain that electrically stimulate a precise area with only an injection in the arm. This approach could someday help to treat deadly or debilitating brain diseases and remove the related risks and costs of surgery.

Massachusetts Institute of Technology (MIT) researchers have made major strides toward making this sci-fi possibility into reality.¹ They created microscopic, wireless bioelectronics that could traverse the body’s circulatory system and autonomously self-implant in a targeted region of the brain, where they would then administer focused treatment.

The noninvasive alternative is a nonsurgical implant consisting of immune cell-electronics hybrids, which the researchers call “circulatronics.” The subcellular-sized, wireless, photovoltaic electronic devices harvest optical energy with high power conversion efficiency.

In a study on mice, the researchers demonstrated that after injection, the tiny implants can spot and travel to a specific region of the brain without needing human guidance. Once there, they can be wirelessly powered to deliver electrical stimulation to the precise area. This neuromodulation has shown promise as a method to treat brain tumors and diseases like Alzheimer’s and multiple sclerosis.

Because the electronic devices are integrated with living, biological cells before injection, they’re not attacked by the body’s immune system and can cross the blood-brain barrier, leaving it intact. This way, the barrier’s crucial protection of the brain is preserved. The researchers said the biocompatible implants don’t damage surrounding neurons.

The MIT team has been working on their circulatronics for over six years. The devices are each about one-billionth the length of a grain of rice and composed of organic semiconducting polymer layers between metallic layers to create an electronic heterostructure.

They’re built using CMOS-compatible processes in MIT.nano facilities, then integrated with living cells to create the cell-electronics hybrids. To accomplish this, the researchers lift the devices off the silicon wafer that they’re fabricated on, so they’re free-floating in a solution.

Deblina Sarkar, the AT&T Career Development associate professor in the MIT Media Lab and MIT Center for Neurobiological Engineering, head of the Nano-Cybernetic Biotrek Lab, is the senior author of a study on the work. She’s 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 electronics worked perfectly when they were attached to the substrate, but when we originally lifted them off, they didn’t work anymore. Solving that challenge took us more than a year,” Sarkar said.

The researchers leveraged a chemical reaction to bind the electronic devices to cells—they fused the electronics with monocytes, which target areas of inflammation in the body. They also used a fluorescent dye so they can trace the devices as they cross the blood-brain barrier and self-implant in the target brain region.

The Sarkar lab is working to develop the technology to treat multiple diseases including brain cancer, Alzheimer’s disease, and chronic pain. The researchers said the capabilities of circulatronics devices could make them ideal to treat brain cancers like glioblastoma that cause tumors at several locations, some of which might be too small to identify with imaging. They can also offer new ways to treat especially deadly cancers like diffuse intrinsic pontine glioma, an aggressive tumor in the brain stem that can’t usually be surgically removed.

“This is a platform technology and may be employed to treat multiple brain diseases and mental illnesses,” Sarkar said. “Also, this technology is not just confined to the brain but could also be extended to other parts of the body in [the] future.”

The circulatronics also allow the biocompatible devices to live with neurons without causing harmful effects. Through biocompatibility testing, the researchers found that circulatronics can safely integrate among neurons without impacting cognition or motion.

The researchers aim to power the technology into clinical trials within three years through MIT spinoff company Cahira Technologies, a recently launched startup. They’re also examining integration of additional nanoelectronic circuits into their devices to allow functions like sensing, feedback based on on-chip data analysis, and creating synthetic electronic neurons.

“Our tiny electronic devices seamlessly integrate with the neurons and co-live and coexist with the brain cells creating a unique brain-computer symbiosis,” said Sarkar. “We are working dedicatedly to employ this technology for treating neural diseases, where drugs or standard therapies fail, for alleviating human suffering and envision a future where humans could transcend beyond diseases and biological limitations.”

Reference
¹ www.nature.com/articles/s41587-025-02809-3