- Scientists have found a new way to communicate with battery-free devices implanted inside the body.
- These tiny devices are powered by radio waves that are harmless to human tissues.
- It can be used to monitor internal conditions and deliver drugs at appropriate times.
For many years scientists all over the world have been trying to bring wireless networking capabilities to advanced in-vivo sensors and actuators. The existing medical devices like cardiac pacemakers have inbuilt batteries, which make their size relatively large.
These devices are usually injected or swallowed into the body to analyze brain circuits, monitor internal vital signals, and deliver drugs at appropriate times. However, their biocompatibility and networking capabilities are quite limited.
Recently, researchers at MIT and Brigham and Women’s Hospital created a new technique to communicate with battery-free devices implanted deep inside the body. These devices can monitor internal body signs, deliver drugs and cure infections by stimulating the brain with light or electricity.
These tiny devices are powered by radio frequency waves that can pass through the human body without harming any tissue. Although they aren’t equipped with batteries, physicians can communicate with them from a certain distance outside the body.
Since these devices do not have a battery, their size can be extremely small – smaller than a grain of rice. The ability to communicate with these battery-free devices would be a huge advance and can open new doors for several medical applications.
For example, brain implants that can be powered by external signals could help deliver light to stimulate neuron activity via optogenetics – a biological technique (to treat neurological disorders) that hasn’t been adapted for use in humans yet.
How Power Is Transmitted To Implanted devices?
So far, transmitting energy has been a challenging task because radio waves aren’t powerful enough to supply energy through human tissue. To overcome this challenge, scientists developed a system called In-Vivo Networking that uses a group of antennas emitting radio waves at slightly different wavelengths.
As these waves travel, they overlap in several manners. At highest overlapping points, they deliver enough energy to power this tiny device.
Since the energy is transferred over a wide area, knowing the exact position of device(s) in the body isn’t necessary. Thus, these radio waves can power more than one device simultaneously. Along with energy, the waves also carry signals that tell the device to release drug, a pulse of light, or a burst of electricity.
In this study, researchers tested the device in pigs. They successfully demonstrated that a device placed 10 cm deep in the tissue can be powered from a distance of one meter away from the body (using In-Vivo Networking). Moreover, one can power the device from up to 38 meters, if it’s placed very closed to the surface of the skin.
The scientists are currently trying to make the process of energy transfer more efficient over longer distances. Along with the medical field, this technology can also enhance radio frequency-associated applications in other fields, including retail analytics and inventory control, and enable greater-distance object tracking.