Tiny "Liquibot" Robots Need No Electricity, But "Feed" on a Solution to Delivery Their Payload
Running entirely on chemical reactions, these tiny spheres can dive down to retrieve chemicals and delivery them to the edge of the jar.
A team of scientists at the Department of Energy’s Lawrence Berkeley National Laboratory (Berkeley Lab) and the University of Massachusetts Amherst have shown off tiny liquid-based robots — capable of running without electricity, so long as they can find "food."
"We have broken a barrier in designing a liquid robotic system that can operate autonomously by using chemistry to control an object's buoyancy," says Tom Russell, senior author of the paper and professor of polymer science and engineering, of the "liquibots" his team has developed. "We don’t have to provide electrical energy because our liquibots get their power, or 'food,' chemically from the surrounding media."
The robots are small — less than 2mm (around 0.08") in diameter — and operate entirely chemically: They retrieve chemicals from the middle of a solution that causes them to generate oxygen, lifting the robots to the surface; a separate reaction pulls the robots towards the edge of the container where the chemicals are offloaded — causing the robots to sink again.
"The cyclic buoyancy-induced cargo shuttling occurs continuously," the team notes in the paper's abstract, "as long as the supply of reactants diffusing to the sac or droplet from the surrounding aqueous phase is not exhausted" — in other words, so long as the liquibots can find "food" in the medium in which they swim.
The team says that the liquibots, though small, could prove useful — including multitasking on workloads like the detection of different gases and chemicals or the screening of small chemical samples for everything from disease diagnoses to drug discovery and synthesis.
The work has been published under closed-access terms in the journal Nature.