MIT researchers have developed an injectable antenna that could power battery-free medical implants, offering a groundbreaking solution for deep-tissue medical devices. This tiny antenna, measuring about the size of a fine grain of sand, can receive power from low-frequency external magnetic fields, making it a potential game-changer for various medical applications.
The researchers, led by Baju Joy, a PhD student at the MIT Media Lab's Nano-Cybernetic Biotrek research group, have published their findings in the October issue of IEEE Transactions on Antennas and Propagation. They believe this technology can revolutionize the way we power medical implants, particularly those used in cardiac patients (pacemakers) and individuals with neurological conditions like epilepsy or Parkinson's disease.
One of the key advantages of this injectable antenna is its size. At just 200 micrometers, it operates at low frequencies (109 kHz), which is a significant improvement over current options. The current methods for powering deep-tissue implants involve either surgically implanted batteries that need periodic replacement or magnetic coils that are placed surgically and operate at high frequencies, causing tissue heating and limiting power delivery when miniaturized.
The MIT team's innovation lies in a novel technology that combines a magnetostrictive film (which deforms when a magnetic field is applied) with a piezoelectric film. This combination converts deformation into electric charge, allowing the antenna to harness mechanical vibrations and convert them into electric fields. This unique approach enables the antenna to deliver 4-5 times more power than similar implants using metallic coils and GHz frequency ranges.
The antenna's design is reminiscent of a rechargeable wireless cell phone charger. It can be applied as a stick-on patch or placed in a pocket close to the skin surface, generating a magnetic field that activates the antenna. The researchers have also fabricated the antenna using the same technology as a microchip, ensuring easy integration with existing microelectronics.
This system can be placed in the body with a simple needle injection, and the researchers envision scaling antenna manufacturing to treat large areas of the body. Beyond pacemakers and neuromodulation devices, the technology could also be applied to glucose sensing, opening up a world of possibilities for battery-free medical implants.
Baju Joy emphasizes the versatility of this technology, stating, 'We can leverage all these other techniques that are also developed using the same fabrication methods, and then just integrate them easily to the antenna.' This injectable antenna represents a significant step forward in the field of medical implants, offering a less invasive and more efficient way to power life-saving devices.
