The examination of biological cells and tissues under the microscope is critical for several reasons. Identifying the recognizable elements for abnormalities and normal states.
Microscopy places a vital role in all areas of biology, botany, and zoology. The core event in the process is mounting the specimens on slides for observation.
This makes it crucial to understand the jargon of microscopy. In this section, we will shed more light on the most used techniques for preparing slides in microscopy.
What does the abbreviation wm stand for?
‘wm’ is the acronym for the whole mount. It represents the process of mounting an entire organism or specimen on the slide.
The organism or specimen should be thin or tiny enough to be mounted directly. The most used specimens in this technique are unicellular and multicellular organisms.
What cs stand for?
‘cs’ is an abbreviation used for cross-section slide mounting. A very thin portion of a specimen, such as an earthworm wafer, is mounted on a microscope slide.
The cross-section is cut perpendicularly or longitudinally. These cross-section styles of mounting are used quite commonly in microscopy.
What does ls stand for?
‘ls’ is an abbreviation for a longitudinal section placed on a slide. A section of the specimen is cut lengthwise. In other words, it is dissected parallel to the longitudinal axis.
Preparation of microscope slides
It is important to ascertain that you have all the material required ready for observation. These materials include the specimen mounted slide, coverslips, pipets droppers, and chemicals.
Typically, there are two basic types of slides used for microscopy. The flat glass slide and the well or depression slide.
Both slides are rectangular. The widely accepted measurement for microscopic slides is 1 × 3 inches.
The indentation in the center of the slide is meant for holding liquid droplets. These slides are more cost-effective than flat slides. These can be used without a coverslip.
Plastic or glass is the most commonly used materials used in manufacturing microscopy slides. The typical thickness of these slides is typically kept at 1 to 1.2 mm thick.
When working with high power objectives or condensers, the thickness must be reduced. It is better to procure more number of slides since they break easily while conducting observations.
A coverslip, on the other hand, is an ultra-thin piece of glass or plastic. It is placed after a drop of water is added to the slide.
The water droplet is used for creating surface tension. When the coverslip is placed on top of it, the dome of the droplet flattens.
This allows the observer to focus the high power objective closer to the specimen. The coverslip is also meant for reducing the specimen to a single plane.
This effectively reduces the amount of time needed for focusing on the specimen. The coverslip also invariably protects the objective’s lens from coming in contact with the liquid droplet.
Slide preparation techniques
The different methods of placing the samples on the microscope can be summarized into four basic types. The wet mount, dry mount, squash, and staining.
The dry mount
Dry mounting is the conventional technique of placing a specimen on a slide. You need to place a thin section right in the center of the slide. Follow this by placing the coverslip.
This mounting technique is best for observing the features of airborne particles. It is necessary to keep the specimen fine for proper illumination.
The mounts are used for dead matter or inorganic substances. Therefore these types of mounts have remarkable longevity.
The wet mount
As the name suggests, wet mounts are used for aquatic organisms or specimens. These organisms are places in brine, glycerin, or other types of immersion oils.
To prepare a wet mount, you will need specific equipment. These equipment include pipettes, tweezers, paper tissues, and a liquid used for microscopy.
The application of wet mounts extends to a wide range of microscopic specimens. But they are also quite transient. As the liquid dries up, the organism dies.
Squashing
Squashing is used for soft specimens. You need to apply a similar technique as that of a wet mount for preparation.
Begin by placing the tissue over the coverslip. Press down the system gently. You need to apply a gentle touch not to break the glass or the squash sample.
Staining
You can employ several methods for slide staining in microscopy. These include vital and non-vital stains.
Staining is used for creating a deep contrast. This contrast helps reveal the patterns and details of a specimen.
There are several ways of staining a slide. These include methylene blue, iodine, and crystal violet dyes. Stains can be added to both dry and wet mounts.