Wireless pacemaker placed in rabbit

Tiny electrostimulator The wireless pacemaker is just 3mm long

US researchers have built a wirelessly powered pacemaker the size of a grain of rice and implanted it in a rabbit.

They were able to hold a metal plate a few centimetres above the rabbit's chest and use it to regulate the animal's heartbeat.

If such medical implants could be made to work in humans, it could lead to smaller devices that are safer to fit.

The findings are published in the journal PNAS.

The researchers from Stanford University hope their development could also eventually dispense with the bulky batteries and clumsy recharging systems that are currently a feature of such devices.

The central discovery was a new type of wireless power transfer that could safely penetrate deep inside the body, using roughly the same power as a cell phone.

"We need to make these devices as small as possible to more easily implant them deep in the body," said co-author Dr Ada Poon, from Stanford's department of electrical engineering.

There are broadly two categories of electromagnetic wave that have been considered until now: far-field and near-field.

Far-field waves, like those broadcast from radio towers, can travel long distances, but either bounce off the body harmlessly, or are absorbed as heat.

Near-field waves can be safely used, but they can only transfer power over short distances.

The researchers were able to design a device that blends the safety of near-field waves with the reach of far-field waves.

"With this method, we can safely transmit power to tiny implants in organs like the heart or brain, well beyond the range of current near-field systems," said John Ho, a graduate student in Dr Poon's lab.

More Science & Environment stories


Features & Analysis

  • Salim Rashid SuriThe Singing Sailor

    The young Omani who became a prewar fusion music hit

  • Spoon and buckwheatSoul food

    The grain that tells you a lot about Russia's state of mind

  • A woman gets a Thanksgiving meal at a church in FergusonFamily fears

    Three generations in Ferguson share Thanksgiving reflections

  • Canada joins TwitterTweet North

    Canada's self-deprecating social media feed

BBC Future

Manmade islands require redrawn maps (Getty Images)

The last unmapped places

Uncharted regions closer than you think


  • All-inclusive holidaysThe Travel Show Watch

    With all-inclusive holidays seeing a resurgence are local trades missing out to big resorts?

BBC © 2014 The BBC is not responsible for the content of external sites. Read more.

This page is best viewed in an up-to-date web browser with style sheets (CSS) enabled. While you will be able to view the content of this page in your current browser, you will not be able to get the full visual experience. Please consider upgrading your browser software or enabling style sheets (CSS) if you are able to do so.