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Electron Microscopy Sciences

Technical Data Sheets

Tissue Culture Monolayer Embedding Mold: Thompson Mold

EMS Catalog #70924

This mold is designed for embedding mammalian cells in monolayer culture in preparation of sectioning for electron or light microscopy. We suggest using Spurr's resin (EMS #14300) or EMbed-812 resin (EMS #14120). Araldite resin may not polymerize well in the deep troughs of this mold.


  1. Coat a 22 mm x 22 mm glass coverslip with TFE-like spray or mold release agent (EMS # 72619).
  2. Polish the excess off.
  3. UV sterilize each side of the coverslip in a tissue culture dish -usually a 35 mm dish (EMS #70340).
  4. Grow the cells on it.
  5. Fix and dehydrate. Fixation and contrast of tissue culture cells is best with McDonald Osmium-ferricyanide fixation.
  6. Process through Spurr's resin (remove all air bubbles by spinning at 2000 rpm/5').
  7. Fill the mold troughs with above Spurrs.
  8. Turn the coverslip cell side down on top of the mold, press down gently to make sure no air-bubbles are present.
  9. Cure at 70°C overnight, or 65°C for 48 hours.
  10. Cool at room temperature; 2-3 hours.
  11. Pop coverslip off, using flat edge forceps, (if coverslips do not release well dissolve off coverslip in hydrofluoric acid for 10 minutes, rinse very well in water. Let resin slabs dry for 1 hour.
  12. Gently push bottom of mold to release resin slabs.
  13. Pull resin slabs out gently with hemostat or forceps.
  14. With a jewelers saw and vise, saw slabs in half or one third.
  15. Mount in a vertical chuck.
  16. Trim and section.

With any luck, you should be able to obtain 6 to 9 blocks to section per coverslip -bubble free and ready to be sectioned without extra gluing onto stub, etc...

Product Information

Tissue Culture Monolayer Embedding Mold: Thompson Mold