Fig. 1: Edible aquatic robot concept, design, and work principle.

a Future application scenarios of edible aquatic robots. b The multilayer structure of the aquatic robot made from edible materials, which comprises a boat-shaped body to provide buoyancy and various nutrients, and a fluidic actuator that encloses the fuel reservoir and the reaction chamber. c Sectioned structure view and working principle of the fluidic actuator. Only upon contact with the water surface, the effervescent reaction will be triggered and produce the gas pressure that allows the fuel to be dispensed through the outlet. The oleogel sealant is applied to guarantee an airtight fit between the reaction chamber and bottom fluidic layer, which is crucial for the functioning of the device. d Top view of the fuel dispensing and propulsion procedure. The fuel decreases the liquid surface tension behind the aquatic robot, creating the tension gradient that drives forward motion.