I am looking at collecting samples of mouse plasma for an ELISA. Since the samples themselves are so small, and we would like to do more a survival blood draw, we are looking to pool the samples from several mice receiving similar treatment for their EAE. My question is, will there be any degredation, if the samples are frozen, thawed, and then frozen again?
Hi Michael,
I suppose this depends on the nature of the analyte. I have thawed a previously-thawed sample and run an ELISA on it (both for largish peptides...) and encountered no problems. Why do you have to pool the samples? Perhaps it would make more sense to aliquot samples according to how much you'll need for each ELISA? We typically get about 300ul plasma following a cardiac puncture at end-point, which is more than enough, or are you doing serial draws?
Cheers!
Ross
Hi Ross,
We are doing serial draws, so we might be getting about 50-100ul of plasma per mouse (rough estimate). It was just a thought I had before setting up a blood collection study on mice.
Thanks!
Michael
It indeed depends on what you're looking at.
Most proteins remain stable at -20 for a couple of months or at -80 for longer.
Just make sure to avoid to many freeze-thaw episodes...
May I suggest you do a control test by taking mouse plasma and runing it through several thawing cycles. If you analyse after say every thawing cycle you would be able to determine whether you lose analyte. Alternatively you may add a control group say 5 mouse plasma samples of which you know the analyte concentration to start with and alow it to thaw with you samples each time you thaw your experimental samples. Then upon running your assay you would be able to mathematically correct for the amount of analyte lost through repeated thawing.