Biodegradable and Edible Milli‐Fluidic Logic Circuits

ABSTRACT Recent years have seen a rise in the development of biodegradable and edible electronics for medical and robotic applications, but fluid‐based circuits and computation with biodegradable and edible materials remain a challenge. Here we describe methods for developing milli‐fluidic logic circuits that are fully biodegradable and edible. These circuits are made of logic gates with a novel, pre‐stressed, gelatin‐based valve. These gates operate at low pressure (∼5 kPa) and display a pressure gain (the ratio between output and input signal) greater than one, which is required for the design of complex logic circuits made of cascaded logic gates. We model the valve by finite element analysis and validate its performance experimentally. We then demonstrate a set of foundational logic gates (NOT, NOR, and NAND) that all exhibit pressure gains greater than one. Finally, we fabricate and operate two cascaded logic circuits, including a one‐bit memory unit and a ring oscillator, that display reliable operation for extended periods of time. The methods and results described here provide the foundation for the design of fluidic logic systems capable of computation and control of fully biodegradable and edible robots for medical and environmental applications.