New wireless tech lets implants transmit data through ions in tissue
Transmitting data from medical implants in the body can be tricky, but researchers at Columbia University have now developed a new technique that essentially writes data to ions in human tissue, where it can then be read from a receiver outside the body at high transmission speeds.
Implantable electronic devices are important for healthcare, as they can monitor activity in the heart, brain or other organs and alert doctors to issues. But getting that data out of the body is a hurdle – running wires through tissue can risk infection, while wireless technologies like radio, light, ultrasound and Bluetooth don’t penetrate human tissue very efficiently.
So for the new study, the Columbia researchers developed a new technique that can wirelessly transmit data by taking advantage of the body’s own communication method. Cells in the body exchange ions to communicate with each other, so the team tapped into the electrical potential energy stored in tissues.
The new ionic communication method starts by implanting a pair of electrodes inside tissue that can encode data from a device in alternating electric pulses, then stores that energy in the ions inside the tissue. Another pair of electrodes can be placed on the surface of the tissue, such as the skin, to receive the stored energy and decode the data.
The team says this technique could be used to transmit data through tissue as deep as 10 cm (3.9 in), while losing less signal than radio frequency communication does at any depth. The transmission speed was also faster than other techniques, with the scientists recording rates of up to 60 MHz, with room remaining for optimization.
In tests in live rats, the researchers paired these ionic communication systems with neural interface implants. Over the course of a few weeks, the devices were able to transmit data successfully to the external receivers, and were precise enough to pick up signals from individual neurons.
The team says that ionic communication requires lower voltages and power than other wireless technologies, which should make it more viable for implants. Devices making use of the technique could also be made fairly easily from soft, biocompatible materials.
The researchers say the next step is to create and test an implantable biosensor using organic transistors that can use ionic communication.
The research was published in the journal Science Advances.
Source: Columbia University