Cell culture on silastin membranes

[Ed Frank]

I am trying to culture C2C12 (mouse skeletal muscle) cells on Silastin 
membranes (polydimethylsiloxane).  Though I washed the membranes 
overnight in PBS pH 7.4 and coated them with Pronectin F prior to 
plating, cell adhesion was poor on the membranes themselves but normal 
on the tissue culture plastic just beyond the membrane borders.  If you 
are familiar with this system and can offer some insight into inproving 
attachment I would appreciate your input.