MEA & cell culture

I'm using MEA's standard version. Initially I had wonderfull confluent cell cultures, but after using them 15-20 times, I only get some clumps of cells, that die very soon. It seems as if I miss a coating, but I've tried all the advised coatings without succes.
Do you have the same experiences, and does someone have good results with a (cardiomyocyt) cell culture & coating or is it normal that after 15-20 times of use are exhausted?
Thanks for help,
S. Beeres, reseach docter

Dear S.Beeres,

if the MEA is stored in dry air for a long time this could result in
loss of hydrophilic property of the MEA surface and could lead to a bad
attachment of either the coating and/or the cells.

Please send detailed information about how you have treated the MEA
(cleaning/coating procedure, time of use, etc..) to
"support@multichannelsystems.com" in order to discuss this issue more thoroughly.

With best regards

Michael Fejtl