Progress towards the integration of technology into living organisms requires electrical power sources that are biocompatible, mechanically flexible, and able to harness the chemical energy available inside biological systems. Conventional batteries were not designed with these criteria in mind. The electric organ of the knifefish Electrophorus electricus (commonly known as the electric eel) is, however, an example of an electrical power source that operates within biological constraints while featuring power characteristics that include peak potential differences of 600 volts and currents of 1 ampere1,2. Here we introduce an electric-eel-inspired power concept that uses gradients of ions between miniature polyacrylamide hydrogel compartments bounded by a repeating sequence of cation- and anion-selective hydrogel membranes. The system uses a scalable stacking or folding geometry that generates 110 volts at open circuit or 27 milliwatts per square metre per gel cell upon simultaneous, self-registered mechanical contact activation of thousands of gel compartments in series while circumventing power dissipation before contact. Unlike typical batteries, these systems are soft, flexible, transparent, and potentially biocompatible. These characteristics suggest that artificial electric organs could be used to power next-generation implant materials such as pacemakers, implantable sensors, or prosthetic devices in hybrids of living and non-living systems3,4,5,6.
We are grateful to B. Rothen-Rutishauser and A. Petri-Fink at the Adolphe Merkle Institute for the use of their 3DDiscovery printer. F. Bircher’s iPrint institute at the Haute École d’Ingénierie et d’Architecture Fribourg, particularly F. Bourguet and M. Soutrenon, donated time towards adapting a printer for our use and helped us to understand the intricacies of microvalve printing systems. Laser cutting was performed at Fablab Fribourg. U. Steiner’s group, in particular P. Sutton and M. Fischer, provided instrumentation and advice related to impedance measurements. Research reported in this publication was supported by the Air Force Office of Scientific Research (grant FA9550-12-1-0435 to M.M., J.Y., D.S. and M.S.) and the National Institute of General Medical Sciences of the National Institutes of Health under award T32GM008353, which funds the Cellular Biotechnology Training Program (T.B.H.S.). The content is solely the responsibility of the authors and does not necessarily represent the official views of the National Institutes of Health.
This video shows fluidic artificial organ implementation.
This video shows printer depositing gels for serpentine implementation.
This video shows Miura-ori folding of a gel-bearing substrate.