Here come the rice-grain-sized brain implants: Stanford discovers way of beaming power to microimplants deep inside …

Stanford electrical engineer and biological implant mastermind, Ada Poon, has discovered a way of wirelessly transmitting power to tiny, rice-grain-sized implants that are deep within the human body. This could well be the breakthrough that finally allows for the creation of smaller pacemakers, body-wide sensor networks, and a new class of electroceutical devices that sit deep in the human brain and stimulate neurons directly, providing an alternative for drug-based therapies for depression, Alzheimers, and other neurological ailments. There will of course be the potential for elective, transhumanist applications as well.

The key to this discovery is a new method of wirelessly transmitting power, dubbed mid-field powering. As the name implies, mid-field power transfer uses radio waves that sit between near-field (tens of gigahertz) and far-field (tens of megahertz). Near-field radiation can penetrate human flesh, but can only effectively transfer power over a short distance (millimeters). Far-field waves can transfer power over longer distances, but are unfortunately scattered or absorbed by human skin. To create mid-field waves, Poon created a patterned antenna (pictured below) that generates special near-field waves. When these special waves hit the skin, they turn into mid-field waves that can then penetrate a few more centimeters of flesh.(For more on how wireless power transfer actually works,read our explainer.)

Mid-field power transfer, using a special antenna

Currently, as theres no good way of (safely) wirelessly transmitting power through human flesh, implants generally need to contain a large battery, which in turn makes the implant way too large to embed deep within the body. As a result, most implants so far have been either large-battery pacemakers that sit just under the skin (with long electrodes that reach into the heart), or cochlear (ear) implants that are near enough to the skin that near-field power transfer is feasible.With the advent of mid-field power transfer, Poon and her friends at Stanford have created rice-grain size implants that can be embedded directly into the heart to function as a pacemaker, or attached to a nerve bundle.

Poon has tested the technology in pigs and rabbits, and humans are next. Stanford says that independent testing has shown the radiation produced by mid-field power transfer is well within safety limits for human exposure. In short, the prognosis for human testing of these microimplants is good. [DOI: 10.1073/pnas.1403002111 - "Wireless power transfer to deep-tissue microimplants"]

Current implants (here the implant powering a retinal prosthesis) are rather large.

The question is, what might we do with such microimplants? Both heart and brain pacemakers (for Alzheimers) are the obvious first port of call. Beyond that, though, microimplants would make great sensors; you could implant them all over your body (brain, heart, liver, gut) and have them regularly report that organs health back to your doctor (or smartphone app). As we begin to learn more about the brain, we might attach these implants to specific nerve channels in the brain, to boost or degrade specific neuron behavior. We might boost the ability of the hippocampus to create long-term memories, to improve learning but block the signals that tell synapses to uptake serotonin, mitigating depression. (Read: Do we need a bill of rights for our future, implanted brains?)

Or maybe, in some kind of utopian transhumanist future, wed just have a bunch of implants dotted around the brain, so that we can use our smartphone to trigger the release of various hormones at any time. Feeling down? Here, have some oxytocin. Need a boost of energy? Just push the adrenaline button. Need to chop your hand off or commit some kind of high-risk, armed felony? Slide the endorphin bar all the way to the right.

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Here come the rice-grain-sized brain implants: Stanford discovers way of beaming power to microimplants deep inside ...