Membrane Storage

It may be desirable to store a western blot for future analysis or reprobing. An advantage of PVDF (polyvinylidene difluoride) membranes over nitrocellulose is the stability of PVDF. PVDF is a chemically resistant polymer that has excellent long term stability. Therefore, it is possible to store a PVDF membrane and preserve sample proteins for extended periods of time by following the protocol below.

Storing a Blot Protocol

1. Sandwich the dry PVDF blot between two clean sheets of Whatman 3MM paper.


2. Place the sandwich between two sheets of card stock or thin cardboard.


3. Use paperclips to clip the stack together on the edges.


4. Place the stack in a plastic bag and seal the plastic bag closed.


5. Store the blot at 4˚C for up to 2 weeks, -20˚C for up to 2 months, or -70˚C for longer storage.
   
   
   • Note: Thaw frozen blots to room temperature before removal from the plastic bag because frozen blots are prone to breakage.
   
   
   • Note: Blots can also be stored wet at 4˚C, but sodium azide should be added to prevent bacterial growth. As sodium azide inhibits HRP activity, it should be thoroughly washed out of a blot prior to use.