Biological systems use multiple ion species in parallel to communicate, process and store information. Inspired by this, the field of bioiontronics aims to create artificial systems that can interface with biological systems through ions and biological molecules1, and with the help of biomimetic or bioinspired designs2. A range of bioiontronic devices have already been developed, including biphasic gel devices with an internal structure similar to that of water-in-oil emulsions3. In the biphasic gel, ions experience hydration–dehydration cycles when hopping between the aqueous droplets under electric fields (Fig. 1a). This process enlarges the discrepancy in transfer energy among ion species and leads to the separation of different ions, which is useful for ion-selective biological modulation. Writing in Nature Electronics, Ziguang Zhao and colleagues now report an ion transporter that is based on a multiphasic gel and can be used for ionic neuromorphic processing4.