Re-embedding Tissue

If previously embedded tissue is of a wrong orientation, it can easily be cut out of the Epon block and re-embedded.

 

Materials: hot plate, small aluminum pie plate, Epon blocks containing mis-oriented tissue, long forceps, new single edge razor blades, wooden block (approximate size 5 to 8 inches long x 1 to 2 inches thick x 2 to 4 inches wide. A piece of flat wood is a good surface to razor cut the Epon block on), fresh Epon resin mixture, flat mold or Beem capsule, printed label, gloves, safety glasses, fume hood.

 

Procedure:

  1. Place all work materials under the fume hood. Set the hot plate to highest temperature it is capable of.

  2. Once the hot plate is very hot, place the aluminum pie plate atop the hot plate.

  3. Work with one block at a time. Place the Epon block, tissue side up, into the pie plate for heating.

  4. Heat the block for only 1 to 3 minutes; then use the long forceps to remove it from the pie plate.

  5. Transfer the block to the nearby wooded block or some flat, even surface for razor cutting.

  6. Quickly, before the block cools, trim off the biggest area of Epon in one cutting stroke.  See diagram:

    The Epon should be soft, like rubber. If it is not soft, then return it to the pie plate for a few more minutes of heating. Never allow the block to heat more than a few minutes at a time, since it can be easily burned and the tissue can be damaged beyond repair.

  7. You can remove more surrounding Epon from the tissue if you wish. Place the tissue block back into the pie plate for heating, always tissue side up.
  8. This time, the smaller block will heat more quickly, so remove this block after 30 to 45 seconds.
  9. Then trim the excess surrounding Epon while the block is still rubbery. Use a new razor blade as needed. See diagram:
  10.  Once the tissue is adequately trimmed of excess Epon, it then can be re-embedded in fresh Epon and cured in a 60 degree C oven for 48 hours.

  11. To re-embed the tissue, the routine embedding procedure is followed. See protocol on routine embedding procedures, if needed.