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Hank Green: If you are a frequent viewer of SciShow, and I hope you are, you know there's one thing that I can't resist, and that's good solid jellyfish science.  I've talked to you before about Turritopsis dohrnii, the species also known as the immortal jellyfish, because it can revert back to a younger version of itself, and over on CrashCourse, we've talked about how the world's first jellies were the common ancestors of all true animals.  
Well, I today have some breaking jellyfish news for you!  Scientists have created an ersatz jellyfish from scratch that can swim and even create the currents that natural jellies use to eat.  It's called 'the Medusoid' and its a product of an experiment by scientists at Harvard University and Caltech, who wanted to see if and how they could create living muscle.  This is known as tissue engineering and it's one of the pioneering new fields in synthetic biology.  Researchers use these small simple moon jelly as a model for creating a flat, eight-armed template out of flexible silicone.  They then applied muscle cells, taken from a rat's heart, sorry, rat, and grew those cells into real muscle tissue.  When they dropped the fully developed Medusoid into salt water and applied a small electrical current, it swam just like a real jelly and recreated the same motions jellies use to wash food into their mouths.  

Now, the Medusoid doesn't have a mouth or a brain or anything else for that matter, so of course, it's not a real jelly, in fact, it's genetically a rat, but the Medusoid does prove that we can grow live moving muscle tissue and that can be used for all kinds of applications, testing medicines for instance, and it also paves the way for technology that will allow us to maybe even grow entire organs in a lab, like synthetic hearts.  In the meantime, presumably because they had so much fun with this one, the team says it wants to reverse engineer more marine animals to perfect the technique and to learn how to reproduce different animal forms and behaviors.  And if they're really interested in doing this, I have just two words for them: colossal squid.  Please.  

The research appears in the new issue of the journal Nature of Biotechnology, thank you for watching this episode of SciShow, if you have ideas or comments for us, you can leave those on Facebook or Twitter or of course, in the YouTube comments below.

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