This looks like a re-discovery of a 2014 University of Texas at Dallas paper - https://science.sciencemag.org/content/343/6173/868 ?
I am missing something? You can see the hackaday article about this here: https://hackaday.com/2014/02/21/researchers-create-synthetic...
Here is another, earlier iteration also from MIT: https://gizmodo.com/mits-new-plastic-muscles-could-bring-us-...