The Last Jedi is on the big screens, Christmas carols are all around the streets, kids have already looked secretly at their presents.. and while the festive atmosphere fills the air, I am writing my PhD thesis.

In the search for the best dissertation title, I have shortlisted:

  1. What Bobafett and a chick have in common?
  2. How to use The Force to study biology?
  3. Pietrisycamollaviadelrechiotemexity

Only number 3 is true and scientifically accurate, but also quite depressing (translated from Sunny Baudelaire’s language to English, it sound something like “I must admit I don’t have the faintest idea of what is going on” – according to Lemony Snicket). Therefore I have to choose between the first two options. Seeking for your help in my difficult task, I better explain a little bit more.

Bobafett and chick have at least one thing in common: lasers. Chick embryos are very convenient models for the study of embryonic development. You can literally crack a fertilised egg open and have a sample ready to use. There is a surprisingly huge amount of processes that are shared in all organisms during the early phases of their development, and while we don’t develop beaks and feathers as humans we can use chick embryos to study a phenomenon called gastrulation. 

Primitive streak Rabbit
Vagina shaped thing Primitive streak in rabbit embryo (source: Wikipedia).

During the process of gastrulation, the bunch of cells that previously formed the chick embryo reorganise into a multilayer structure, preparing to differentiate into different cells types. The strongest visual sign of the gastrulation process is the formation of a  primitive streak: the isotropic symmetry of the initial embryo is broken, front/back top/bottom left/right symmetries are initiated through the invagination of the tissue.

Other than the awkward shape taken by the organism at this point, the cells in the embryo are facing lots of challenging problems during this process. They need to coordinate all together, and they undergo an immense quantity of mechanical stress. They contract in the posterior area of the embryo before to be pushed toward the streak. Mechanical stress is the keyword for this post to exist at all. Whereas there are mechanical properties involved, you might need a physicist!

To understand more about the whole process of development, we must know more about The Force the cells exert on each other. And to measure forces, as you all know by now, we can use optical tweezers!

Ta-dah!!! There you go! Bobafett with his laser gun and me using a laser to manipulate chick embryo! (I’ll admit: the link is a bit stretched but I am a geek and Bobafett is really cool)

Here is a short summary of how I spent my days over the last two years: in a dark room shooting a laser at a vagina-shaped organism. Or, if I want to use a sentence that doesn’t completely annihilate my self-esteem, in the last two years I used light-matter interactions to study life itself while it was happening. In fact, humour aside, it has been quite exciting to discover that it was possible to use optical tweezers to directly deform cell-cell junction in the living embryos and see what sort of reaction we could measure. For example, we have discovered quite interesting results on the possible origins of tension in the cells in different locations of the embryo. But more on this after I complete my thesis.

Almost forgot! Here is a cute chick to wish you all a great winter break


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