Parafomaldehyde on MEA for immunostaining

We are culturing neuronal cells on MEA system and can record them.

Now we would like to perform immunostaining after the recording to analyze the cell populations with several markers, and use the MEA for a next culture afterwards.

I've seen in several papers that immunostaining (fixation with 4% paraformaldehyde - permabilization - staining) is applicable on MEA, but I still have questions :

- is it possible to use again for culture a MEA system previously treated with paraformaldehyde ?
- Should we apply a specific procedure to clean the MEA that was treated with 4% paraformaldehyde ?
- Is the paraformaldehyde then completely removed or does some stays and perturbs the coating of the next culture ?

thank you
kind regards
Nicolas Heck, Mainz, Germany

Dear Nicolas Heck

>I've seen in several papers that immunostaining (fixation
>with 4% paraformaldehyde - permabilization - staining) is
>applicable on MEA, but I still have questions :

Organic solutions such as paraformaldehyde do not damage MEAs. Anorganic acidic or basic solutions can severely damage MEA electrodes or insulation layer. Please make sure that the permeabilization and staining procedure do not include those solutions.

>- is it possible to use again for culture a MEA system
>previously treated with paraformaldehyde ?
>- Should we apply a specific procedure to clean the MEA that
>was treated with 4% paraformaldehyde ?

As paraformaldehyde is used for fixation of the biological material, it might be more difficult to remove the tissue. A broadband protease treatment could probably help.

>- Is the paraformaldehyde then completely removed or does
>some stays and perturbs the coating of the next culture ?

If the biological material was removed, there also should be no residue of the paraformaldehyde, especially if the MEA is thoroughly rinsed with water or autoclaved after the cleaning.

These comments are from the manufacturer's point of view, but I would like to encourage some users to add comments on their experience with immunostaining.

Best regards, Christine (MCS)