For each experiment that requires PBS + BSA (PBSA), I prepare it freshly and store it at 4oC if there are any leftovers. But for how long can it actually be stored? Does the shelf-life differ with percentages (5% for example)?
I do not know what is the purpose of your solution. If it is for immuno, I will be able to use for a week. SInce it does not have Pen/Strep, try to use within a week, or freeze it,
Dear Ijsbrand, dilute protein solutions (< 1 mg/ml) are more prone to inactivation and loss as a result of low-level binding to the storage vessel. Therefore, it is common practice to add “carrier” or “filler” protein, such as purified bovine serum albumin (BSA) to 1-5 mg/ml (0.1-0.5%), to dilute protein solutions to protect against such degradation and loss (poor shelf-life). Bovine serum albumin solution on its own is highly soluble in water. Buffers prepared from salts like phosphates and chlorides naturally reduce that solubility hence present higher chances for precipitation. Coagulation of bovine serum albumin is irreversible. On the other hand, PBS tends to retard microbial activity in the solution thus extending shelf-life. The more the solute concentration, the less the water activity and the less microbial activity and therefore longer the shelf-life. For additional reading please see the attached.
The purpose of the PBSA solution is just as a blocker for immuno assay.
Hi Ijsband,
If the PBS-BSA solution is for blocking it is stable (reliable) for approximately one week at 4c. Should you wish to prepare cytokine aliquots using PBS-BSA I would personally use it immediately or within 2-3 days, before long term storage in -80.
Good luck!
We dilute our antibodies in 0.1% BSA in PBS and keep the solution in the refrigerator. It is good for months.
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