To begin inoculate 2 million pan02 cells in 12 milliliters of DMEM, and incubate at 37 degrees Celsius and 95%humidity, 5%carbon dioxide, and 35%air. After 48 hours centrifuge the culture at 28 g for 2 minutes and discard the supernatant. Fix the cells by adding 1 milliliter of 2.5%glutaraldehyde in the 1.5 milliliter micro centrifuge tubes overnight at 4 degrees Celsius.
The next day centrifuge the samples at 1006 g for five minutes and aspirate the fixative before rinsing the sample twice with 0.1 molar PBS. Subsequently, rinse the samples twice with double distilled water for 10 minutes each. Next, add a 50 microliter solution of 1%osmium tetroxide and 1.5%potassium ferrocyanide at a ratio of 1 to 1 and incubate at 4 degrees Celsius for 1 hour.
Centrifuge and rinse the samples twice with 0.1 molar PBS and once with double distilled water. Then add 1 milliliter of 1%thiocarbohydrazide and incubate at room temperature for 30 to 60 minutes. After incubation centrifuge and discard the supernatant before rinsing the samples 4 times with double distilled water.
Next, add 50 microliters of 1%osmium tetroxide and allow it to be fixed at room temperature for 1 hour. Centrifuge again and rinse the samples 4 times with double distilled water. Add 1 milliliter of 2%uranyl acetate and allow it to stain at 4 degrees Celsius overnight.
After rinsing the samples with double distilled water add 1 milliliter of Walton solution and incubate at 60 degrees Celsius for one hour. After incubation rinse the cells 4 times with double distilled water before dehydration in a graded ethanol series for 10 minutes each. Then dehydrate twice in one milliliter of 100%acetone for 10 minutes each.
Next, mix 200 microliters of acetone with Pon 812 epoxy resin at a ratio of 3 to 1, 1 to 1, and 1 to 3. And soak the samples in the resin at room temperature for 2, 4, and 4 hours respectively After respective incubation impregnate the samples overnight in 100%Pon 812 epoxy resin. The next day, transfer the specimens into a flat embedding mold and polymerize them in an oven at 60 degrees Celsius for 48 hours.
After polymerization, using an ultra microtome, collect serially sliced strips of 70 nanometers thickness on the hydrolyzed silicon wafers and dry them in a 60 degrees Celsius oven for 10 minutes.
