Yes, there might be protests as scientists are ‘playing God’ again, but the news is too exciting to stoop to such petty protests. Scientists have mimicked the movement of a mammalian heart and made an artificial jellyfish, which can swim using the exact movements that the heart undergoes when it pumps blood. The body of the jellyfish is made up of silicone with cardiac tissue from a rat mounted on this scaffolding.
Heart and the Jellyfish
The researchers from Harvard University and California Institute of Technology (Caltech) noticed the similarities between the pumping motion of a heart and the pumping motion that helps a jellyfish swim. This is the latest in the emerging field of synthetic biology. Says Kevin Kit Parker, one of the people involved in the study:
I started looking at marine organisms that pump to survive. Then I saw a jellyfish at the New England Aquarium and I immediately noted both similarities and differences between how the jellyfish and the human heart pump.
And thus was born ‘Medusoid’. The main challenge was the lack of understanding of how the heart muscles actually co-ordinate themselves via electrical signals. Then they performed something called ‘reverse engineering’. To understand how a medusa jellyfish really swims and how the muscles are all co-ordinated, the team used techniques from biometrics and crystallography. They were also able to understand the exact biomechanics of the propelling muscle contractions.
Getting everything to work together
It turns out that the mammalian heart muscles move in much the same way when they pump blood. Thus, the plan was to make the jellyfish out of cultured cardiac tissue taken from a rat. Silicone would provide the scaffolding that the structure needed. Then they matched the Medusoid with a real medusa jellyfish, part by part. They made sure that the Medusoid was a copy as long as cellular architecture went.
Less tricky was the design of the silicone structure. They had to ensure that the structure pushed water efficiently, like the jellyfish has evolved to do. Too much gap between the ‘legs’ and water would just ‘leak’ through. Too little and you’d just be wasting precious power for thrusting. The cardiac muscles were stimulated by electrical signals.
The work has been reported in Nature Biotechnology in this paper. Lead author of the paper is Janna Nowroth, a research student. His PhD advisor John Dabiri, an expert of biopropulsion is also an author of the paper. Kevin Kit Parker, another coauthor, is an expert in the field of tissue engineering. He had created artificial ‘organisms’ that can grip and pump. The jellyfish was really ambitious!
So what’s the next step? Endowing the jellyfish with something that even it doesn’t have – a brain. The team wants to put a small control center for the nerves so that it can decide where it wants to go.