Hi all,
I’ve made a custom antibody detection ELISA with a Corning Co-Star plate. Coated with antigen, followed by blocking and drying. Ran the standards on the plate and got good recovery (+/- 10%). The next week, I ran the same standards on the same plate, and while I got good recovery again, the OD values had shifted lower by almost 20%.
I’m not sure why there has been a shift, because all the material was stored at the right temperature.
So, I ran a short accelerated stability study to check where my main degradaption was occurring. kept two of the three variable components (plate, detection, standards) at 2-8 C, and used the third component fresh.
According to these studies, it’s the standards that have the maximum degradation (about 110% drop in OD values in 10 days). The other two were degrading by ~10-20%.
What do you recommend for stabilising the standards? As I’m looking to keep this ELISA for at least 6 months.
Hello Krisha Jain
The standard degrades on account of improper storage temperature as well as incorrect buffer used to reconstitute the standard. As mentioned, you have been storing the standard at proper temperature. Have you properly reconstituted the standard in the right buffer and right pH? Usually, purity of protein used as standard also matters.
Regards.
Hello.
Various conditions can be used to store the standard: storage in a refrigerator, freezer, lyophilization, storage in a concentrated form, in an acidic or alkaline medium, in an organic solvent, etc. Сhoose the one that suits your substance. It may also be necessary to add stabilizing additives. I would recommend freezing, lyophilizing and storing in a concentrated form in the freezer. But it is difficult to give advice without knowing anything about the standard.
Hi Krishan, I'm assuming your standard in column purified immunoglobin. We routinely added proclin 300 to ours and stored in polypropylene tunes. The proclin helps prevent microbial degredation and the polypropylene minimizes loss due to adherence to the storage vessel. The points raised by the other 2 members are all very valid considerations as well. You can buy proclin 300 from sigma. Best of luck
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