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Developed by Rice University engineers in collaboration with Texas Medical Centre institutions, the nerve stimulators are the first proof-of-concept results from a years-long programme to develop tiny, wireless devices that can treat neurological diseases or block pain. They require no batteries, and instead draw power and programming from a low-powered magnetic transmitter outside the body.
The MagnetoElectric Bio Implant (Me-Bit) is placed surgically, and an electrode is fed into a blood vessel towards the nerve targeted for stimulation. Once there, the device can be powered and securely controlled with a near-field transmitter worn close to the body.
The team, led by Jacob Robinson and Kaiyuan Yang of the Rice Neuroengineering Initiative and Sunil Sheth of the University of Texas Health Science Centre’s McGovern Medical School, successfully tested its technology on animal models and found it could charge and communicate with implants several centimetres below the skin.
The implant could replace more invasive units that now treat Parkinson’s disease, epilepsy, chronic pain, hearing loss and paralysis, the team said.
“Because the devices are so small, we can use blood vessels as a ‘highway system’ to reach targets that are difficult to get to with traditional surgery,” Robinson said. “We’re delivering them using the same catheters you would use for an endovascular procedure, but we would leave the device outside the vessel and place a guide wire into the bloodstream as the stimulating electrode, which could be held in place with a stent.”
The ability to power the implants with magnetoelectric materials eliminates the need for electrical leads through the skin and other tissues, the researchers said. Leads like those used for pacemakers can cause inflammation, and sometimes need to be replaced. Battery-powered implants can also require additional surgery to replace batteries.
Me-Bit’s wearable charger does not require surgery, and can even be misaligned by several centimetres and still sufficiently power and communicate with the implant.
The programmable 0.8mm2 implant includes a strip of magnetoelectric film that converts magnetic energy to electrical power. An on-board capacitor can store some of that power, and a ‘system-on-a-chip’ microprocessor translates modulations in the magnetic field into data. The components are held together by a 3D-printed capsule and encased in epoxy.
The research suggests endovascular bioelectronics like Me-Bit could lead to a wide range of low-risk, highly precise therapies. Having electrodes in the bloodstream could also enable real-time sensing of biochemical, pH and blood-oxygen levels to provide diagnostics or support other medical devices.
The team ultimately hopes to employ multiple implants and communicate with them simultaneously. “That way we could have a distributed network at multiple sites,” said Robinson. “Other things we’re looking to add are sensing, recording and back-channel communications so we can use the implants to both record and stimulate activity as part of a closed system.”
The work was detailed in Nature Biomedical Engineering.
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