• Question: how did you and yours identify this 'invisibility cloak'? where you testing for natural compounds similar to something you cam up with yourself or did you identify something in the makeup of the seaweed or its behaviors or growth?

    Asked by anon-249966 to Katrina on 23 Mar 2020.
    • Photo: Katrina Wesencraft

      Katrina Wesencraft answered on 23 Mar 2020:

      I definitely didn’t come up with it myself! The first time scientists successfully coated cells in a polymer was in the 1930s so this idea has been around for almost 100 years. The first human trial where alginate coated cells were implanted in a person was in the early 1990s – so you can see how long these things take to develop! My research is about how to coat the cells most effectively, but other people I work with are creating ‘invisibility cloaks’ with new compounds. The thing we like about alginate is that it’s a ‘bioinvisible’ polymer – so the material can be implanted without bothering your immune system. The circulating white blood cells either can’t detect alginate, or they decide to ignore it for some reason. We create a tiny jelly bubble (200 micrometres diameter – about the width of a human hair) and trap the cells inside. Alginate is selectively permeable, so nutrients can get in to feed the cells, while compounds that the cells produce can get out (I work with cells that produce insulin). The pores in the material allow these substances to flow in and out, but they’re too small for large immune cells and antibodies to get in. This should stop the cells inside from being attacked by the immune system.