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STANFORD (CBS 5) — In the 1966 movie “Fantastic Voyage,” a submarine full of scientists is shrunken to microscopic size and injected into the bloodstream of a seriously wounded diplomat to dissolve a blood clot in the brain. Today the idea is no longer science fiction.
From cochlear implants to pacemakers, implantable medical devices are becoming smaller and smaller. Researchers are working on a class of medical devices that are so small they can travel through the bloodstream.
Stanford professor and electrical engineer Ada Poon has been working with PhD candidates Anatoly Yakovlev and Dan Pivonka for more than four years to develop a swimming microchip.
“We encountered a lot of obstacles along the way and then we solved them one by one,” said Poon.
Medical implants are generally powered by batteries, and batteries take up a lot of space in a device. Professor Poon’s device is battery-free, powered wirelessly by electromagnetic radio waves.
“We use this energy to power up the electronics in the implant, to drive the locomotion, command the implant to move forward or steer, turn left or right,” said Poon. Once inserted into the bloodstream, the tiny device swims around with great precision.
Pivonka explained that a four-by-four centimeter antenna is used to transmit both power and data to the microchip.
“The transmission frequency is two gigahertz and we transmit data at up to 20 megabytes per second,” Pivonka said.
With a maximum power of about two watts he said, “It should be safe to transmit these signals through human tissue without causing any damage and still powering the device and sending data.”
The prototype device is 3mm-by-4mm, and the limiting factor is the size of the receiving antenna.
“If we were to reduce the receive antennae, the device would receive less power but as we scale the device down it should be able to move at the same speed if we make it smaller,” Pivonka said.
The researchers hope to shrink the device even further. Poon explained, “Because right now the device could go through the arteries, but we want it to even go through some smaller bloodstreams.”
These tiny devices are a technological marvel that may one day change the face of medicine. “This (device) could carry some drugs for more precise drug delivery, or it could have sensor elements for diagnostic purposes, or even for use in surgery,” Poon said.
Poon says there is still much room for improvement before her team can start testing the device in humans. They hope to make it swim faster and make it small enough to fit into a needle so it could be injected directly into a blood vessel. And they want to make it biodegradable to eliminate worries about removing the device.
“We are pretty excited about it, but this is only the first step. We still have a long way to go in order to realize this fantastic voyage,” Poon added.
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