Text and illustrations
below are excerpts from an article, entitled:
Toolbox for Working With Living Invertebrates by
Toolbox contents >)
to be published in
Proceedings of the Association for Biology Laboratory Education
(ABLE), vol. 26, 2004
V. Tape well slides
Purpose of tool:
slides are well suited for non-destructive observation of small organisms that
are encapsulated in a relatively thin and uniform plane of focus. The slides are
especially useful for viewing living, whole specimens of aquatic oligochaetes,
such as Lumbriculus variegatus (Drewes and Lesiuk, 1999). These worms are
thigmotaxic, and thus prefer refuge in the narrow space between the floor of the
well slide and the cover slip. These well slides are also excellent for viewing
water samples containing microorganisms such as protozoa, rotifers, nematodes,
Clear plastic tape [Brands: (1) Frost King clear plastic weatherseal tape; 2 in x 100 ft roll; sold at home improvement stores, or on-line
Colored Plastic Tape: Clear, Cat. #190; 0.75 in x 125 in
Metal straight edge ruler
New, single-edge razor blade
Heavy-duty, flexible clear plastic [Suggested materials: Lexan
clear polycarbonate sheet (30 mil thickness), or extra-heavy clear plastic
lamination sheet, or thin plexiglass][Alternate: glass microscope slides]
Assembly and use of this
- Use a marking pen and
straight edge ruler to mark off the desired rectangles that will become the
floors of the tape well slides (Fig. 10).
- Carefully align a long strip
of clear tape over a series of the rectangles, as shown in Fig. 10. If wide
(2 in) tape is used, it is important to minimize air bubble formation under the
tape. To minimize such bubbles, use one finger to press down and smooth the
tape, beginning at the center line of the tape and working outward toward the
- Add multiple layers of tape,
NOTE: Each layer of Frost King weatherseal tape adds approximately 75
microns (0.075 mm) of depth to the well. Each layer of Scotch Clear Plastic
Tape adds approximately 60 microns (0.060 mm) of depth to the well. Three layers
of weatherseal tape nicely accommodate average-sized blackworms (Lumbriculus)
in the wells.]
- Using a metal ruler and new
single-edge razor blade, make vertical cuts through the tape layers, as shown
in Fig. 11. These cuts define the well size. Make sure cuts are overlapping at
the corners. This insures easy removal of the tape that covers the well.
- Now, insert the tips of a
sharp-tipped forceps under the corner of tape covering one well. Lift the
corner of tape to remove all tape layers covering the well (Fig. 11).
- Next, use a heavy scissors
to cut out the rectangles from the sheet. Use a single-edge razor blade to
trim away any tape that extends over the edges of the cut rectangles.
- Cut two narrow strips of
tape and attach them to the underside of the well slide, as shown in Fig. 12.
These tape strips act as spacers or feet that slightly elevate the well
slide above the microscope viewing stage, thus helping to reduce scratching or
marring of the floor of the well slide.
Figure 10. Rectangles on transparent sheet covered by multiple layers of clear
Figure 11. Suggested position and size of cuts for tape well slides. Note that
forceps tips are used to pry up the tape at one corner of the well.
- On a clear transparent
sheet, mark off a series of rectangles that define the cover slips to be used
over the tape wells. The size of the cover slips should be larger that the
well but slightly less that the length and width of the tape that it will rest
on (see Fig. 12).
- Use a plastic pipet (or
stretch pipet, as shown in Figs. 7 and 8) to place a living specimen in the
well, along with a few drops of water.
- Cover the fluid-filled well
with one of the cover slips made in step 8. Press slightly on the cover slip
and tilt the slide sideways to drain off excess water drops. Now, the specimen
is ready for viewing
- CAUTION: Be sure the
microscope light does not overheat organisms in the well slides.
- After making observations,
carefully slide the cover slip off the well and use a pipet to flush the
organism back into its original container.
- Wells should be rinsed
thoroughly in distilled water and air-dried.
less than 10 cents per well slide. Assembly time is less than 10 min/unit.]
Completed tape well slide showing size and position of cover slip. Note the
tape feet on the underside of the well slide (dotted lines).