In this video, released yesterday, you can watch what might be called the world's first cyborg lifeform. Called a medusoid, it's a completely engineered jellyfish that blends living and non-living parts — specifically, the creature is a thin layer of rat heart muscle cells grown on top of a layer of elastic silicone. The result is a creature that swims like an ordinary jellyfish. Created by a group of bioengineers at Caltech and Harvard, the medusoid could be the first real step toward cyborg life.

Working with Harvard biophysicist Kit Parker, Caltech biotechnology researcher Janna Nawroth based the medusoid on the common moon jelly, which swims by rapidly contracting its bell-shaped body and then slowly opening the bell back up again. Using rat heart cells, she was able to emulate the jelly's propulsion system. The medusoid's muscle cells contract smoothly when exposed to an electrical current in water. Then, the silicone part of its body gently springs the creature back into a flat shape. Each time the rat heart cells "beat," the jelly contracts and moves forward.

Nawroth and her colleagues built the medusoid partly as a proof-of-concept that a simple lifeform like a moon jelly could be reverse-engineered and then replicated with biological and non-biological parts. In a paper published yesterday in Nature Biotechnology, the scientists write that the medusoid demonstrates how a "biologically-powered mechanical device . . . can be designed and incorporated into synthetic organisms that precisely mimic the biological function of the desired organism." In other words, they've shown that biotech machines can behave like living creatures.

But this project didn't begin as a bid to create a new kind of life. The groups' work was inspired by an interest in organ repair. Parker told Nature's Ed Yong that he hopes the medusoid can be used to test heart drugs. In their paper, the researchers also suggest that this work grows out of the quest for better artificial organs.

Still, the researchers are not shying away from the fact that they've built a new kind of organism — and they intend to build more complicated ones as soon as possible. Write the authors:

At this stage, swimming behavior is limited . . . we have no means of fine-controlling local muscle contraction to achieve, for example, turning and maneuvering. However, the future integration of multiple cell types and compound materials will allow for constructs of greater autonomy that are capable of sensing the environment and employing internal decision-making circuits to choose a suitable response from a variety of behaviors.

Essentially, they're saying that they'd like to create a cyborg that can make decisions based on input, and whose body will be complex enough to do more than just swim forward.

At what point will such a creation be considered alive, rather than just a "biologically-powered mechanical device"? Over the next decade, we are going to find out.

Read the full scientific paper via Nature Biotechnology.