Powering implants deep inside the body has long been a challenge. Existing devices rely on bulky batteries that require surgery for replacement or on magnetic coils that can overheat tissue when operating at high frequencies. Both options limit the size and depth to which such devices can be placed.
The new approach uses magnetoelectric materials, which convert magnetic energy into electrical energy through mechanical vibrations. Operating efficiently at low frequencies, this mechanism can safely deliver power to tiny implants with minimal tissue heating.
Magnetoelectric Design
Central to the study is a 200-micrometer antenna, about the size of a grain of sand, that combines two thin films: a magnetostrictive layer, which deforms in response to a magnetic field, and a piezoelectric layer, which generates electrical charge when strained.
When exposed to an external magnetic field of roughly 109 kHz, the magnetostrictive film flexes, transferring mechanical stress to the piezoelectric layer and producing an electrical signal.
The antenna is manufactured using standard microchip techniques, facilitating scalable production and easy integration with electronic components. Its small size means it can be injected with a needle rather than surgically implanted.
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Results And Performance
Laboratory modeling and measurements indicate that the antenna can deliver four to five orders of magnitude more power than metallic coil antennas of similar size that operate in the gigahertz range. Because it works at a low frequency, simulations and benchtop tests suggest the device remains well within safety limits for tissue heating.
The team’s results confirm that efficient, low-frequency wireless power transfer is possible even at sub-millimeter scales, an obstacle that has long stood in the way of deep-tissue bioelectronics.
Future Applications
The magnetoelectric antenna can be paired with sensors to monitor signals such as glucose levels, neural activity, or cardiac rhythms. Its compatibility with microelectronic fabrication means it could power multiple miniature devices simultaneously for long-term health monitoring.
By enabling battery-free, minimally invasive implants, the technology could eventually support continuous physiological monitoring and targeted therapies as research progresses toward clinical translation.
Reference
Press Release. MIT News. Injectable antenna could safely power deep-tissue medical implants. Accessed on 29th October 2025.