Nothing particularly interesting happened last week, and I realised that I haven‘t talked much about what I‘m doing at this lab yet. I was a bit apprehensive about writing about it at first, actually, because thanks to the scientific blogosphere I was recently made aware of the horrors of something called prior publication and the debate whether it‘s ethical to blog about one‘s own work. But I figure as I‘m only doing something that just about everyone* working with cell cultures is doing, it‘s OK.
This post was somewhat prompted by a conversation I had with a new curious friend (I love new curious friends). It went somewhere a long this line:
– So, what do you do during this internship?
– Right now I‘m just growing cells. Trying not to kill them.
– And how do you do that?
– Well, I keep them in a sort of flask and the cells attach to the bottom. We put some liquid that has all sorts of good things that the cells eat in it. When the cells eat up all the good things, the liquid changes colour (from raspberry pink to yellowish), and I need to suck it out and put in new liquid. And also cells divide and multiply and eventually they cover the whole bottom, then I need to pry them off and take only a little part of them and put them in a new flask.
– And how do you pry them off? With some very small tools?
(Here I paused for a moment because I had a very vivid image of myself trying to pry cells from a bottom of a flask using tweezers whose ends are so thin that one can‘t see them.)
– No, we use certain chemical materials. Cells hold onto the flask using proteins, and we use an enzyme trypsin** that sort of melts those proteins. We put some of it into the flask and after a short while the cells come off. I suck them out with the liquid and only take a little part of them to put into a new flask.
I‘m actually not sure if I managed to explain it that well during the actual conversation. In any case, this is basically what I (mostly) do. However, while it sounds fairly straightforward in theory, it is rather more complicated in reality. For one, all the work has to be done with your hands inside a box that looks something like this:
(Image from Wikimedia Commons)
The glass only comes up a little. Like, probably less than 30 cm. It‘s like working through a cat flap. I‘m still not used to it and get annoyed with it at times. Also, you have to be careful not to contaminate your materials and your cells. So, you have to be careful not only about what you touch but also about holding your hands above certain things. I’ve only done the cell detaching procedure by myself a couple of times now and every time I work I get so tense that afterwards I‘m actually shaking. Hopefully, by the end of the internship, I‘ll be confident enough and skilled enough not to get so stressed.
The second lesson I‘ve learnt so far: if you don‘t know what you‘re doing, find and ask a person who actually knows the stuff you‘re doing. If such person is not available, look at some articles on the topic or something, before you actuallly do something.
And finally, I‘m going to explain the last lesson I‘ve noted so far using a baking analogy, because baking makes everything better. So, let‘s say you have 3 new fancy baking dishes that you have never used before and cake batter that you never made before. So, you don‘t know how it will turn out (based on previous experience with other cakes, you have, however, a couple of ideas about it). These baking dishes are very fancy – they are all flippy-flappy and you can turn them inside and out. During preparation process you suddenly notice that you can‘t tell which is the right side out or in anymore. So what do you do? You turn them inside/out at random and fill them with your batter and bake all three cakes at once. Then they all don’t look how you expected, and you don‘t know if that‘s because they‘re the wrong side in or just because that‘s how cakes turn out in these baking dishes. So, you don’t actually find out how the cake is supposed to turn out. What you should have done is just try one dish and after noticing that you lost the in- and out- sides, make sure not to do that with the other dishes and not bake them all at once. At least not until you can handle it all***.
Wondering if that might be the most complicated cake analogy ever,
*I wonder how many people there are who work with cell cultures, in the world… 100 000? 10 000? More? Less? I wonder how one goes about finding that out. Thoughts?
**Incidentally, trypsin is the same stuff that breaks down proteins in our stomachs into the tiny aminoacids so they can be absorbed by our organisms. That’s what it does to the proteins that cells use to attach to the flask. Are you wondering now, how come the stuff doesn’t break down the proteins of the cells of your stomach?
***Sometimes you also need to know that each dish produces the same result. So, next time you might want to bake a few cakes together in order to avoid the result being different just because you use different brand of flour or something.