How many times can the antibody be reused in western blot?

It's varied in different antibodies, or even in the same antibody with different lot numbers. Usually when we find no bands (signal) with the reused antibody, or when the properties of the antibody are changed (color, settling), we must stop to reuse it. Hope you find it helpful.

In general, the primary antibody solution can be used 3-5 times, and save it at -20 after each use, if bands signal the last time is weak it is not recommended to use it again, if the solution volume is small and it can not be without PVDF membrane, an appropriate amount of PBST\TBST-milk can be added and then the same antibody can be added in proportion to the newly added solution to continue use.

Antibodies can be reused. However, the stability of the protein stored at -20 ℃ will be affected by repeated freezing and thawing, so it is recommended to store at 4℃. To avoid microbial contamination, sodium azide (0.1%) can be added as a preservative and used repeatedly until antibodies clumps or signal weakens.