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templelane
Mar 28, 2007, 07:45 AM
Does anyone know what the difference is between a cell based assay and an in vitro assay? They seem the same to me! Is in vitro a whole tissue? That is the only difference I can think of. Cheers for any help:)

manimuth
Apr 1, 2007, 08:33 PM
Actually, I believe that "cell based assay" goes under the label of "in vitro assays" (in addition to "enzyme assays", "binding assays", "immunoassays", etc- they are all in vitro assays)

Cell based assays work with living cells, outside of a living thing, in a controlled environment (the definition of "in vitro"). So, in short, cell based assay is a type of in vitro assay.

Hope this helps.

templelane
Apr 3, 2007, 11:45 AM
Thanks that's what I initially thought but I was asked to compare and contrast which confused me. How can you do that if they are basically the same? Anyway just said a bunch of stuff about how in vitro that isn't cell based was easier to scale up for industry but could miss possible handles. Thanks for replying

medgen
Apr 4, 2007, 06:07 PM
It is a little foggy, but to most biochemists, a 'cell-based' assay would be in vivo (although to a macrobiologist this might be considered in vitro. Essentially (again, to a biochemist), in vitro (literally "In glass") assays are those that take place removed from the actual living system. Usually you will have a fractionated part of a cell, or even just an enzyme or two, as your assay. In contrast, while most cell-based assays are nowadays done 'in glass', by which I mean in a tube of some sort, since the cell is still alive it would generally be considered in vivo.

And having survived many in vivo and in vitro experiments and publications, I can tell you that it is awfully difficult to get most cell biologists to accept work done entirely in vitro. That is, while in vitro is great for dissecting a system into its component parts, you then have to work back up to the in vivo system to prove that your in vitro work is reflected in a real living organism.