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This prototype of an implantable wireless medical device is powered by remotely using ultrasound
<p>This prototype of an implantable wireless medical device is powered by remotely using ultrasound.</p>

Powering Implants with Ultrasound

Medical researchers would like to implant small electronic devices inside patients to monitor certain biological parameters or to deliver treatment and relieve pain. A major stumbling block in these efforts, however, is devising a way to power those implants without using bulky batteries that make the implant too large or running wires from the outside into the implant, an approach that risks infection.

Engineers at Stanford University have devised a way of remotely powering up implants using ultrasound. Ultrasound has proven medically safe and is used in several biomedical applications including fetal and cardiac imaging. It also packs enough energy to power small, millimeter-sized devices.

The key is in the implant. It houses a piezoelectric “power plant” consisting of a small piece of piezoelectric material. Each pulse of ultrasound puts mechanical energy into the material, which converts it into electricity. The electricity runs sensors or is delivered to the patient in a series of small shocks to alleviate pain at its source. The electricity can also power a transmitter to send biometric data to healthcare workers or signal that a task is finished.

The current prototype is about the size of the head of a ballpoint pen. The research team wants to shrink this by a factor of 10. One reason for the smaller device would be to implant a network of sensors in the brains of animals and humans to get more information on neural processing.

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