I need a little help from you dear readers. I need to know the purpose behind culturing cells in a serum free medium. I'm thinking its to control for things like growth factors that are present in serum, but i'm not sure. I have so many other things to find, learn and figure out that I'm hoping you can save me on this one.
pretty please with sugar on top? I'll even tell you how I made Src my bitch.
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10 months ago
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you're right- serum free media allows you to clearly define your media. serum is a slew of things. Plus it changes the lipid content of your cell culture media which can affect dose delivery of whatever you're adding to your cells.
I was taught that anything that isn't exactly defined is bad for you trying to understand regulation of genes.
that said, I always have used non-serum free media since FBS and I are friends... and I wanted my cells to grow the best they could.
Sorry, not to be of more help. If you have any questions about microbes, I'd be happy to help out :)
yep - standardisation. The concentration of growth factors and other chemicals in serum varies from batch to batch.
Also, any cells that may eventually be used for human therapy - even if this is many years down the line - need to be grown without animal products.
One more thing: I think the growth of some cell types may actually be inhibited by serum, especially stem cells.
When wanting to express a secreted protein, using serum-free media reduces the amount of total protein and possible contamination of end product. Also serum is not good for shaker cultures b/c it foams so much. Plus FBS is quite expensive, so if you can grow your cells in reduced-serum or serum-free media, it saves money.
Some reasons people use serum-free cell culture:
(i) When a well-defined medium is required. This way you know that, for eg., there is no growth factor X and so you can add X later and observe the response.
(ii) If you want to avoid unknown contaminants (say, some virus) that may come with serum. If the product has some application in humans for eg., as Cath said.
(iii) I used to make some mammalian cells secrete a recombinant protein. To collect the protein, I leave the cells in serum-free media for one or two days and then collect the media. This way, you don't have to deal with BSA and other major contaminants later during protein purification....as biochembelle said.
(iv) Another significant case is when you want to synchronize the cell cycle timing of all your cells. In serum free media, the cells become quiescent and enter G1/G0 phase. When you add serum later, they all re-enter the cell cycle more-or-less synchronously. I've never used it for this purpose, but I'd guess people who study cyclins and such do it routinely.
I wonder if there is any other major reason.
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Am I allowed to acknowledge blog buddies after my presentation?
Hey, have you read The Immortal Life of Henrietta Lacks yet? I just finished it the other day, it was a great read!
Also, there can be differentiation factors in serum which can push stem-like-cells towards differentiation.
One example- I use ultra-low serum for studying cell signaling.
We use ultra-reduced [10% to 0.5%] serum media for overnight culturing prior to analyzing the mitogen activated protein kinase pathways (MAPKs). Since serum is chock full of mitogens, thus ya know, making your cells grow, it can be helpful to control for that. Though *looking* at your cells funny (and, literally, *swirling* their media too much) can cause phosphorylation of ERK1/2, so they are sensitive pathways.
another example- many (most?) old-school cationic lipid transfection protocols. Apparently something in serum interferes with many of the transfection reagents. Nowadays, many of the reagents are marketed as "does not require the use of serum free media!"
If you are doing work in cancer biology, it is also worth noting that anything that can grow int he absence of serum may better approximate uncontrolled proliferation/cancer type phenotypes. So if you ever switch a cell type from a rich serum media to a low or non serum media, that's something to be aware of.
Also, although I don't know anyone who does it for this reason, I can see ethical reasons to avoid it if you can. FBS is not a nice product.
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