Seeking advice on coated plates storage - (Apr/27/2012 )
Hi. What are recommended (from your experience) storage conditions for coated ELISA plates? I coat them overnight, in the fridge, with BSA-hapten in 50 mM TRIS pH 9.
Can they just be washed (I use low strength TRIS), sealed and put in -20°C freezer?
Should they better be blocked (I use 1% casein in TRIS) and washed before storage?
Is it better to dry (method?) them?
I'd love to hear your opinions.
there was a thread from November last year with some advice
Coat plates the way you normally would. Then block. After decanting fill with your buffer containing 5% sucrose in your blocking buffer; allow to sit 30-1 hr rt. then decant. do not wash do not rinse. dry inverted overnight. Store in sealed plastic bag with dessicant pouch at RT or 4C. This is equivalent to what manufacturers do to produce kits.
You may have to optimize some of these steps since it has been quite some time since i did this. Crucial component is the sugar and bsa as protectants.
With that said....it is my experience that precoated and dried plates rarely match up to those that have been coated the day (or a few days) before and left in the coating buffer. On a number of occasions, I have asked reputable kit manufacturers to keep their pre-coated plates and provide me with the coating antibody in solution resulting in reduced CVs between wells.
If your use is R&D only then leaving the wet solution in sealed plates will be fine. However, if you are storing for weeks, months, to 1 yr then dry is the best approach. Commercial, clinical lab kits with dried plates provide documentation of CV's less than 5%. Additional specifications are usually detailed in kit protocols that are approved by FDA 510(k) process.
Thanks a lot for your advice/suggestions! I didn't want to use preservatives (we have thimerosal and sodium azide, the latter wouldn't be that suitable since I use HRP, though a good washing technique should remove all residues) so I had thought of freezig or drying. I'll see if I can test the different aproaches.