A report in Cell Reports Physical Sciences last month highlighted a charging method using a person’s own breathing movements. This could alleviate the issues caused by the surgery required each time an implantable deep brain stimluator’s batteries need changing.
Most pacemaker batteries last for seven to 10 years, according to the UConn researchers. However, most DBS batteries typically require charging every two to three years. This happens because of their high energy consumption. But, the UConn DBS development never needs its batteries changed.
UConn chemists Esraa Elsanadidy, Islam Mosa, James Rusling and collaborators developed this platform.
Instead of using a battery, the device converts the motion of the user’s chest as they breathe into electricity. The chest wall, with every breath in and out, presses on a small and thin electric generator, called a triboelectric nanogenerator. This converts movement into static electricity. The researchers compared this process to rubbing a balloon on your shirt, then sticking it to a wall thanks to their different static electric charges.
Charges from the more negative material stick to the more positive one. In the DBS’ triboelectric nanogenerator, this creates a current that charges a supercapacitor. The supercapacitor discharges electricity to power the medical device and stimulate the brain.
“We wanted to make this fit in with the rest of the available technology in the usual way,” said Rusling. “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.”
The team conducted testing by embedding the nanogenerator in the chest of a simulated pig. The pig contained a pig lung connected to a pump. When the lung inflates and deflates during inhalation and exhalation, it pushes against the nanogenerator. This causes the nanogenerator to rub and produce electricity.
Once produced, electricity travels through a thin wire to charge the supercapacitor. This powers the DBS electronics placed outside the rib cage. The DBS used electricity to create pulses at a rate of 60 times per second, just like in a commercial device.
“This is the first system that combines all the pieces; efficient energy harvesting, energy storage and the controlled brain stimulator,” said Mosa. “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. The next step will be to try the device in a large animal.
Mosa serves as CTO of VoltXon. The company, part of UConn’s Technology Incubator Program, is commercializing this DBS system.