Self-Powered Microswimmers Created With Three Ingredients

A new study has shown that it's possible to create self-powered swimming robots that are extremely small using three ingredients. Researchers on the project combined oil drops with water containing a detergent-like substance and found they can produce artificial swimmers that can swim independently and harvest energy to recharge. The oil droplets harness fluctuating temperatures in their surrounding environment to store energy and swim.

When cooled, the droplets release a thin tail-like thread into the environment that generates friction between the tail and the surrounding fluid, pushing the droplet causing it to move. When heated, the droplets retract their tails, returning to the original state, harnessing heat from the environment to recharge.

Researchers found the droplets recharge multiple times and were able to swim for periods of up to 12 minutes at a time. Dr. Stoyan Smoukov said that in biology, researchers know that to create the simplest artificial cells requires over 470 genes. However, the new study has shown using a few simple and inexpensive components, a new type of active matter able to change shape and move like a living thing can be created.

Smoukov says he and the team hope the study opens the opportunity for people to engage in cutting-edge science. The only equipment needed is an optical microscope, and people can create the microswimmers in the most basic laboratory setup or at home. Thousands of swimmers can be created per drop of water at a price of about 7p per teaspoon.

The artificial swimmers created using the technique aren't harmful to living things. Scientists hope they can be used to study basic interactions between living organisms and bacteria or algae. Researchers believe by mixing their artificial swimmers with groups of living organisms they can develop a better understanding of how biological microswimmers communicate.