Microscope Slide Preparation

microscopeslideimage

slide - rectangular piece of glass or plastic on which you place the specimen.

coverslipimage

coverslip - thin, square piece of glass or plastic which you place over the specimen on the slide.

preparedslideimage A. dry mount - requires no water (slide, object, coverslip); usually used for inanimate objects that don't require water to live.

Place slide on a flat surface.
Lay specimen on top of slide (use as thin of a specimen as possible - 1 cell layer thick is best).
Place coverslip slowly on top of specimen as flat as possible.

B. wet mount - requires water (slide, water, object, coverslip); used to prepare slides that hold living organisms (mobile or not).

Place slide on a flat surface.
Place a drop of water on the slide. Add the specimen to the drop of water (at times, you may want to have the specimen already on the slide before adding the water).
Hold the coverslip by its sides and lay its bottom edge on the slide close to the specimen. Holding the coverslip at a 45o angle helps.
Slowly lower the coverslip so that it spreads the water out. If you get air bubbles (looking like little black doughnuts), gently press on the coverslip to move them to the edge. If there are dry areas under the coverslip, add a little more water at the edge of the coverslip. Too much water can be dabbed off with a piece of paper towel.
Moving organisms can be slowed down with commercially prepared solutions, such as Protoslo. A few strands from a cottonball added to the water also can help trap and slow down organisms.

C. staining specimens - Lugol's iodine, methylene blue, or crystal violet may be added to specimens in order to increase contrast. The stain can be directly added to the water when first preparing the slide or it can be added later after first viewing the specimen without the stain. Add a drop of the stain along one edge of the coverslip. Placing a piece of paper towel along the opposite edge of the coverslip will help draw the stain under the coverslip. CAUTION: The above dyes will stain skin and clothing. They are also harmful if ingested.

Safety concerns:

Teachers and students, be sure to keep all Chemical, Sharp instrument, and Glass Safety Rules that are specified by the teacher and in all general laboratory experiences when preparing microscope slides for use.