MIT researchers have developed a way to power and communicate with battery-free nano-devices implanted deep within the human body that could be used to treat diseases.
The implants, which are powered by radio frequency waves, are thought to have the potential to be used to deliver drugs, monitor conditions inside the body or treat disease.
Fadel Adib, who is an assistant professor in MIT's Media Lab, is a senior author of a paper on the research which he will present at the Association for Computing Machinery Special Interest Group on Data Communication (SIGCOMM) conference in August.
"Even though these tiny implantable devices have no batteries, we can now communicate with them from a distance outside the body. This opens up entirely new types of medical applications," said Adib.
The prototypes the researchers used were the size of a grain of rice and have the potential to be even smaller because they don't need batteries. For reference, current implantable medical devices such as pacemakers carry their own batteries, which account for most of its size and offers limited lifespan.
Adib has been exploring the possibility of wirelessly powered implanted devices with radio waves emitted by antennas outside of the body, which is usually difficult because radio waves struggle to pass through the human body and end up being too weak to supply enough power.
To boost the communication with implanted devices, the researchers devised a system that they call In-Vivo Networking (IVN) that uses multiple antennas to emit radio waves at slightly different frequencies.
As the radio waves travel, they overlap and combine in different ways. At certain points, where the high points of the waves overlap, they can provide enough energy to power an implanted sensor.
"We chose frequencies that are slightly different from each other, and in doing so, we know that at some point in time these are going to reach their highs at the same time. When they reach their highs, they are able to overcome the energy threshold needed to power the devices," Adib added.
The devices have been tested on pigs and the research showed that the IVN radio waves could send power from up to a metre outside the body to a sensor that was 10cms deep inside the body. Sensors located closer to the skin could be powered from 38 metres away.
The new system doesn't require knowledge of the exact location of the sensors in the body as the power is transmitted over a large area. This means that they can power multiple devices at once.
The sensors receive a signal telling them to relay information back to the antenna, which the research believes can be used to stimulate the release of a drug.
These implanted or even ingestible devices could offer doctors new ways to diagnose, monitor and treat many diseases. For example, the devices could be integrated with neurostimulators that perform deep brain stimulation to treat diseases such as Parkinson's or epilepsy.
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