Working on embryonic stem cells, my cells need feeding EVERY SINGLE DAY! Which means I have to work weekends too 😦 So, I am often getting texts from friends and family simply asking ‘what am I up to?’ and when I’m in the lab on a weekend, the reply is usually ‘In work. Feeding my cells.’ without actually realising that to most of my friends and family that doesn’t really mean anything. So I often get questions back asking ‘What do you feed them?’ and ‘How do you know they are hungry?’. Hopefully this post will explain…
I often use the expression ‘feeding my cells’ as do all of my colleagues and we all instinctively now what each other is referring to. But to those who have no scientific background or have minor interest in what I get up to in the lab, this means very little. So, what do I actually mean? And what am I feeding them? Am I leaving my cells a nice burger and chips to munch their way through each day? Or maybe a salad instead to try and keep my cells happy and healthy? Unfortunately not! My cells get given a delicious red liquid every day called media, which is simply a liquid that contains all the nutrients and growth factors that the cells need to keep growing, and to keep them happy!
How do I know they are hungry? Much like when a baby cries when they are hungry (no, my cells don’t cry!), my cells also send me a sign that they are hungry – by changing the colour of the media.
So, here are some photos of my cells growing in tissue culture plates just after I have fed them on the top, and 24 hours later on the bottom. The big difference is that the culture medium has turned from red to yellow! The more cells that grow, the quicker they use up the nutrients that are in the media. The cells digest these nutrients and release the waste by-products, or metabolites, back into the media. These by-products change the pH of the media, or its acidity, causing it to gradually turn yellow!
So, ‘Feeding my cells’ simply means that I am removing the old, used media from the wells and adding fresh media full of healthy nutrients 🙂 ! Think of it like an all-you-can-eat buffet – you finish round 1, then have to clear your plate before you pile it all back on the plate again!