Portable multi-ionic reverse electrodialysis for continuous power supply and controllable drug release

Bioinspired ionic power devices have been investigated due to their high biocompatibility and potential for sustainable energy conversion through ion concentration gradients. However, recent research into portable ionic power devices has primarily focused on hydrogel-based stacking elements, such as ion-selective gels and ionic reservoirs, to enhance productivity. However, this approach results in ionic resource consumption for the operating time. In this study, we propose a portable ionic power generator that provides continuous electricity by integrating multi-ionic reverse electrodialysis (MRED) with a passive capillary micropump for electrolyte absorption. The integrated MRED system was fabricated on a portable fluidic chip with optimizations of absorbing performance, electrolyte concentration, and shortcut current regulation attaining maximum potential of 267.45 mV and current of 4.42 mA. Furthermore, consistent and continuous performance for 25 min was achieved by incorporating cotton flow resistors, which modulate the electrolyte absorbing rate at the electrolyte contact region of the pumps. The electric potential was controlled by adjusting the cotton mass inspiring controllable drug release via iontophoresis where high voltage enhances charged drug penetration. This study paves the way for a new form of ionic power supply for patch-type wearable health devices.