Human Epidermal Cells
Introduction: What do your skin cells look like? It is easy to remove some and look at them with a microscope.
Biological Concepts: Cell structure and Epidermis
Materials:..........Methylene blue stain, 1% aqueous.....................Microscope...................
...........................Clear tape, 1.0 cm x 1.0 cm................................Microscope slide..........
...........................Forceps.................................................................Slide cover slip.............
...........................Soap/water............................................................Paper Towel.................
Safety Precautions:
Methylene blue is a vital stain – it stains nearly everything, and it is difficult to remove. Prevention is the key when working with vital stains. Avoid contact with eyes and skin. Use forceps to move tape after applying the stain. Wear safety glasses or chemical splash goggles whenever working with chemicals, heat or glassware in the lab.
Procedure:
1. Wash the underside of a wrist that will be sampled for epidermal cells with soap and water.
2. Stick a clean piece of clear tape on the underside of the washed wrist.
3. Gently remove the piece of tape from the wrist being careful to avoid getting fingerprints on the tape. A forceps might help to remove the tape and avoid fingerprinting the tape.
4. Place the tape, sticky-side up, on a clean microscope slide.
5. Stain the top, sticky side of the tape with 1 or 2 drops of 1% methylene blue solution.
6. Use forceps to gently place a cover slip over the sticky tape. Lower one edge of the cover slip down onto the tape without touching the forceps to the tape. This should help prevent staining your fingers. Caution: Use methylene blue carefully. It will stain most items including skin, clothing, and table tops.
7. Examine the slide under a microscope. Look for cells with low power first, and then switch to high power for details.
8. Record your observations of epidermal cells by making drawings. Label your drawings with appropriate magnifications.
Cleanup:
1. Return you microscope to low power and turn off the light.
2. Carefully move the microscope slide to the side of the stage.
3. Grab the cover slip using forceps. If the tape sticks to the cover slip, grab it with forceps and pull it lose. (Use the forceps to stick the tape to a small piece of paper for disposal if needed.)
4. Using the forceps, drop the cover slip in the designated beaker of water.
5. Using forceps, drop the tape in the designated waste can.
6. Without touching the stain on the microscope slide, put the microscope slide in the designated beaker of water.
Source: http://www.flinnsci.com/Documents/demoPDFs/Biology/BF10228.pdf