Researchers from Queen Mary University of London have developed self-powering, three-ingredient, swimming microrobots that swim independently and harvest energy from their surroundings.

The artificial swimmers are composed of a combination of oil, water and a detergent-like substance. The oil droplets rely on fluctuating temperatures from their surroundings for storing energy and swimming.

Under cooling conditions, the droplets develop a thread, or tail. When released into the environment, friction between the so-called tail and surrounding fluid is produced, subsequently pushing the droplet forward. According to the researchers, the droplets can swim for up to 12 minutes at a time.

When heated, the droplets retract their tails and recharge by harnessing heat from their surroundings.

Dr. Stoyan Smoukov, reader in chemical engineering at Queen Mary University of London and author of the study, said: "In biology, research shows that to create even the simplest artificial cells we need over 470 genes. However, through this international collaboration, we show that just by using a few simple and inexpensive components we can create a new type of active matter that can change shape and move just like a living thing."

Because the swimmers are not hazardous to the environment, the researchers believe that they can be used to examine interactions between living organisms such as bacteria and algae.

The research appears in the journal Nature Physics.