Preparation of MicroSlide Smears

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Preparation of Micro-Slide Smears

• Microscope slide preparations may be either wet
  mounts or smears
• Most bacterial cells must be viewed using smear
  preparations that are later stained using various
  types of stains in order to see the cells and
  their structures.
• A smear is a thin preparation of cells spread on
  a glass slide and then allowed to air-dry
• The smeared material is then fixed to the
  slide using heat from a Bacticinerator or burner
  flame.
• The air-drying followed by heat fixing kills the
  bacterial cells and attaches them to the surface
  of the glass slide so that they will not readily
  wash off during the staining procedure.
• Smears can be permanent preparations that may be
  used over and over, whereas, wet mounts are
  normally for one time use and used to view living
  organisms.

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Lab Procedure for Smear Preparations

• Students work individually and prepare their own
  smears.
• Obtain the bacteria sample, usually in Nutrient
  Agar slants, plates, or broth cultures.
• Sterilize an inoculating loop using the
  Bacticinerator and following the proper aseptic
  techniques described previously. Remember to
  always close the opening of the sample container
  once you have your bacteria on the loop!
• If preparing a smear using plates or slant tubes
  add one small drop of tap water to the slide
  surface and then mix the bacteria on the loop
  into the drop of water.
• Spread the water/bacteria mixture on the surface
  of the slide to assist with air-drying and to
  ensure that the smear is evenly spread across the
  surface of the slide.
• Allow the smear to air-dry (2 5 minutes
  depending on how well it is spread)
• Heat-fix the smear by passing it over the top of
  the Bacticinerator (use a clothesline clip to
  hold the slide because it will heat up)
• The smear is now ready to by stained

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Photos of Smear Preparations