This deep brain stimulator needs no batteries, only your breath

Researchers have devised an ingenious way to power deep brain simulators - Using the person's breathing movements.

About 150,000 deep brain stimulators are implanted every year. Normally placed under the skin in the chest area with electrodes implanted in the brain, these stimulators are known to help with neurological and psychiatric diseases when traditional treatments fail. 

So, how does a stimulator work? The brain is zapped by the electrodes with electrical pulses several times per second to regulate the brain's abnormal electrical activity, according to a press release published by the University of Connecticut on November 7.

Research has demonstrated that deep brain stimulators can help people with Parkinson’s disease and largely reduce the symptoms of psychiatric conditions such as treatment-resistant depression and obsessive-compulsive disorder.

However, these stimulators are battery-powered and require changing every two-three years because of their "high energy consumption." Plus, each battery change requires surgery.

University of Connecticut chemists Esraa Elsanadidy, Islam Mosa, James Rusling, and their team found a solution- they developed a deep brain stimulator that never needs its batteries changed.

How does it work?

The device works in such a way that the movement of the user's chest is converted into electricity. As the person inhales and exhales, the chest wall is pressed on a small and thin electric generator called a triboelectric nanogenerator. 

The nanogenerator converts that movement into static electricity. In the deep brain stimulator's triboelectric nanogenerator, a current is created, which charges a supercapacitor. The latter eventually discharges the electricity which powers the medical device and triggers the brain.

"We created our triboelectric nanogenerator using new nanomaterials which produce significant energy output when they come in contact with each other, enough energy to run the deep brain stimulator," Elsanadidy said in a statement.

"We wanted to make this fit in with the rest of the available technology in the usual way. In principle, if someone already has a deep brain stimulator, we could just replace the battery with this generator without having to retrofit them with a wholly new device," said UConn chemist Jim Rusling.

The deep brain stimulator is 'self-sustainable'

The device was tested by embedding the triboelectric nanogenerator in the chest of a simulated pig containing a pig lung connected to a pump.

When the pig breathed, its chest wall pushed against the nanogenerator, causing layers inside the latter to rub and produce electricity. The electricity traveled through a wire to charge the supercapacitor, powering the stimulator electronics placed outside the rib cage. The brain stimulator then used the electricity stored in the supercapacitor to create pulses 60 times a second.

"This is the first system that combines all the pieces; efficient energy harvesting, energy storage, and the controlled brain stimulator. We demonstrated that our self-sustainable deep brain stimulator can intermittently stimulate the brain tissue by alternating periods of stimulation and periods of no stimulation, which is an effective deep brain stimulation approach for treating psychiatric conditions," said Mosa.

The chemists will now try the device on a larger animal. The study paper was published in Cell Reports Physical Sciences.

Study Abstract:

Brain-implanted stimulators are revolutionizing treatment of many neurological and psychiatric diseases, but still rely on temporary batteries for power, which require periodic replacements. Battery-free, self-sustainable deep brain stimulation (DBS) devices remain an unsolved challenge. Herein, we report a self-sustainable, battery-free, intermittent DBS system. This device is enabled by interfacing a high-performance bio-triboelectric nanogenerator (Bio-TENG) as an energy harvester with bio-supercapacitors as fast-charging energy storage units to intermittently drive a DBS pulse generator. The Bio-TENG acts as a smart breathing sensor and biomechanical energy harvester using the inhalation and exhalation motions of an inflated swine lung to charge bio-supercapacitors, which drive the pulse generator to stimulate neurons in mouse hippocampus tissues ex vivo. An intra-electrode triboelectrification strategy is used to boost the Bio-TENG power output. This sustainable intermittent power approach may provide a strategy for powering brain-machine bioelectronics.