Researchers at the Columbia University School of Engineering and Applied Science have developed a new method for implanted devices to communicate with the outside world that exploits the ions that are naturally present in our tissues. Ion-rich tissues store potential energy, and in this paradigm an implanted device would alter this stored energy with alternating electrical pulses. Electrodes placed on nearby skin can then measure these changes in energy and analyze them to obtain the clinical data. The method is rapid and requires low power.
Implantable devices need to communicate with the outside world. Current solutions involve wires that penetrate the skin, which has obvious infection risks and practical barriers for long-term implants. Other methods include using radio waves or light, but these can struggle to penetrate tissue depending on the site and depth of implantation.
In an effort to develop something more effective and reliable, these researchers have turned to ions that are naturally present in our tissues and which cells frequently use to communicate amongst themselves. Ion-rich tissues can be compared to an electric battery, as they both store potential energy. This new technology takes advantage of this to enable wireless communication.
The concept involves an implanted device emitting electrical pulses to influence the potential energy of the overlying tissue. The pulses are emitted in a specific manner to encode clinical data. Then, electrodes planted on the skin over this tissue detect these changes and translate them into usable clinical data. “Ionic communication is a biologically based form of data communication that establishes long-term, high-fidelity interactions across intact tissue,” said Dion Khodagholy, a researcher involved in the study.
So far, the researchers have tested their technology in rats and have shown that it can transmit brain data over a period of weeks. Moreover, the system was sensitive enough that they could isolate the signal for individual neurons. The technology is also highly energy efficient and requires much less power than other modalities, such as radio waves.
Anisotropic ion conducting particulate composite (AIC): Schematic illustration of AIC cross section composed of ions (red and blue), conducting particles (gray), and insulating scaffold (blue); black lines indicate the vertical conduction path (top). Scanning electron microscopy cross-sectional image of AIC film. Colors highlight the sodium polystyrene sulfonate particles (red, 10 micron) and the polyurethane scaffold (purple). Credit: Dion Khodagholy/Columbia Engineering
“The novel material we developed has unique properties that enable the implementation of large-scale organic bioelectronic devices, which can enhance their translation to human health applications,” said Khodagholy. “Next, we aim to design compact and complex anisotropic-ion-conductor-based integrated circuits composed of many organic transistors for bioelectronics applications.”
Study in Science Advances: Ionic communication for implantable bioelectronics
Via: Columbia University