If you are not currently, reusing primary antibodies for your western blots, you’re washing a lot of money down the drain.
In our lab, we regularly reuse primary antibodies at least 3 times before we get rid of them. Some antibodies will work longer than others. In particular, antibodies for post-translational modifications tend to have a shorter shelf-life in terms of saving and reusing. Nevertheless, storing and reusing primary antibodies is a great way to save your lab some money, since the primary antibody is usually the most expensive part of a western.
We save antibodies by first making a 5% Sodium Azide solution in water (THIS SOLUTION IS TOXIC. HANDLE UNDER A FUME HOOD). Add this solution at a 1/100 dilution to your primary antibody solution (usually in 5% BSA in TBST). This gives you a final concentration of .05% sodium azide. This solution will be good for several weeks at 4 degrees celsius.
