Iontronics: A path towards biomimetic information processing

Iontronics is an emerging technology based on ionic devices or circuits in which ions or molecules act as major signal carriers. While the term “iontronics” did not appear in the literature until the 2000s, the origin of the field dates back to 1959, with the rectification of ionic current at a bipolar membrane composed of cation and anion exchange membranes.

Since then, researchers have demonstrated several unique properties of ion-based systems, such as hysteresis and neuromimetic characteristics. Han et al. summarized these advances in iontronics, discussing each iontronic material and its related applications and providing a future outlook on the field.

“Considering the multidisciplinary nature of the field centered around biological systems, we predict that iontronics will keep growing around the borders of biology, neuroscience, chemistry, and materials science,” said co-author Taek Dong Chung. “Meanwhile, it will evolve consistently towards applications in healthcare, prosthetics, and information processing.”

Over several decades, iontronics has evolved using various materials that can selectively control the flow of ions. By carefully controlling the ionic charge carriers, researchers have successfully demonstrated one of the most basic information processing components, the ionic diode. Ionic diodes and other complicated devices, such as ionic transistors and logic circuits, constitute the building blocks for biomimetic information processing.

Iontronics may enable smart, ultrahigh precision drug delivery of ionic species such as neurotransmitters, hormones, and medication directly to target organs.

“Iontronic components may also be used for ion delivery of high temporal and spatial resolution to signal neurons, an important step toward seamless interface with biological systems, including a brain-computer interface at the single neuron level,” said Chung.

Source: “Iontronics: Aqueous ion-based engineering for bioinspired functionalities and applications,” by Seok Hee Han, Min-Ah Oh, and Taek Dong Chung, Chemical Physics Reviews (2022). The article can be accessed at http://doi.org/10.1063/5.0089822 .