The Biosilk foam does not shape properly and it looks flat. What could be the reason?

Make sure a hydrophobic culture plate is being used (e.g. Sarstedt 83.3922.500). If the plate is not hydrophobic, the Biosilk solution will be difficult to pipette and the foam will become flat. Plates that are intended for suspension culture or are non-tissue treated (non-TC) are often hydrophobic.