Abstract
The adhesive tape preparation (Scotch tape prep or cellophane tape prep) for microscopic examination of fungal colonies is a standard technique found in manuals of medical mycology (Forbes et al., 2002). The method is fast and inexpensive and allows direct visualization of fungal morphology. The only disadvantage to this technique is that the preparation dries and the tape wrinkles after several hours, making the preparation unreadable. To use the slide for consultation or education at a later time requires making a fresh preparation. Remaking the slide consumes resources and technician time and causes increased personnel exposure to the organism. We propose a very simple, inexpensive additional step that prevents tape wrinkling and drying, thus extending the useful life of the tape preparation to several weeks. We call this variation the double-layer tape prep'.
The standard cellophane tape preparation is performed under a biological safety cabinet following guidelines for laboratory safety. In the standard tape preparation, a 1.5 inch (40 mm) piece of clear cellophane tape is looped back on itself, sticky side out, using forceps. The loop is gently pressed to the surface of the mycelium (Fig. 1a), then gently lifted and unfolded onto a 25 x 75 mm glass slide, to which three or four drops of lactophenol cotton blue stain has been added (Fig. 1b). The sticky piece of tape with fungal structures will adhere to the slide. The layer of lactophenol cotton blue is the biological stain. The morphology of the fungus is observed without the use of a glass cover slip, as the transparent cellophane tape serves this purpose.