Goal

Visualize cell nuclei in eukaryote cells.

Materials

  • Gas burner
  • 95% alcohol
  • Loeffler’s methylene blue solution
  • Tap water
  • Blotting paper

Method

  1. Prepare a drop of sample on your microscope slide according to our Method
  2. Air dry the sample for 5 to 10 minutes.
  3. Soak the cells in a drop of 95% alcohol to de-hydrate the cells
  4. Air dry the sample for 5 to 10 minutes, make sure all the alcohol is evaporated
  5. Fixate the cells by quickly moving the object glass through a flame.
  6. Let the sample cool down.
  7. Add the Loeffler’s solution for about 60 seconds.
  8. Rinse the slide with tap water.
  9. Air dry the sample.
  10. Cover the sample with a cover slide.
  11. Take a look at the sample through the microscope with the diaphragm fully open.

Composition of the stains

  • Loeffler’s solution: 30 mL of methylene blue in alcohol solution + 100 mL 0.01% KOH solution in water

Gram Stain

Microscopic image of onion cells stained with methylene blue, so the nuclei are visible. Magnification: 100x. - Picture by Umberto Salvagnin CC BY 2.0 license

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