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:
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Place all work materials under the fume hood. Set the hot plate to highest temperature it is capable of.
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Once the hot plate is very hot, place the aluminum pie plate atop the hot plate.
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Work with one block at a time. Place the Epon block, tissue side up, into the pie plate for heating.
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Heat the block for only 1 to 3 minutes; then use the long forceps to remove it from the pie plate.
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Transfer the block to the nearby wooded block or some flat, even surface for razor cutting.
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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.
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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.
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This time, the smaller block will heat more quickly, so remove this block after 30 to 45 seconds.
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Then trim the excess surrounding Epon while the block is still rubbery. Use a new razor blade as needed. See diagram:
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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.
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To re-embed the tissue, the routine embedding procedure is followed. See protocol on routine embedding procedures, if needed.
