To analyse any specimen in your histology lab, you must prepare a perfect histopathology slide first. For this, you should fix the specimen in such a way that light passes evenly through it and demarcates all its significant features. Thus, preparing highest quality slides begins with the few first steps.
What are these first steps?
Here they are:
- Choose the highest quality glass for your slides and coverslips.
- Choose the slides that fit on your microscope equipment and fulfil the purpose of your examination.
- Use the right slide mount.
- Use an effective mounting medium.
- Choose the right slide stains
Let’s discuss these steps in detail:
The glass slide:
- The first step to prepare the highest quality slide is to choose the best kind of slide glass. Some glass slides have floating impurities in them which may create patches of false colour and reduce the contrast and clarity.
- Microscope slides are generally made of optical quality glass. Some are made of soda-lime or borosilicate glass or special transparent plastics of optical quality. Choose one that fits your purpose of the experiment.
- If you will use fluorescent light to illuminate the specimen, use slides made from fused quartz.
- The coverslips should be made of the highest quality optical glass and must be as thin as possible to reduce film effects.
Glass slides are also made in various shapes for different purposes. For example, concave slides have a shallow upper surface to hold liquids. Graticule slides have measurement grids on their surface to aid in counting the cells or assessing the size of the objects. Some slides have special reservoirs and channels cut into them.
Mounting is the process of putting the specimen on the slide. The way the subject is mounted on the slide can affect the clarity of its image. The various slide mounts are:
- Dry mounting places the thin, light, transmittable specimen onto the slide. A coverslip is placed on the top of the specimen to keep it flat and avoid contamination from the microscope’s lens.
- In a wet or temporary mount, the specimen is immersed in water or another liquid on the slide. A coverslip is placed to flatten the specimen and avoid refraction effects from the liquid.
- A permanent mount is used for animal or human tissue studies. All water is removed from the cells of the specimen which is then sliced with the microtome and placed on the slide. A stain is applied to bring out its important features. A coverslip is placed to stabilise and protect the slide.
- Wet mounts use water or glycerol as the mounting media.
- Permanent mounting uses substances which can thicken and hold the specimens in place for a long time, thus, reducing decay and contamination.
- The mounting medium should not act as a lens; otherwise, it will add additional light refraction and distortion. Plus, the mounting medium should have the same refractive index as the specimen.
Stains help to highlight the particular features of the cell anatomy. Varieties of stains are used in a histopathology laboratory depending upon the specific purpose. The quality of your slide also depends on the appropriate use of stains. So, choose wisely according to what you wish to accomplish through your microscopy work.
Taking care of these first steps will help you prepare the highest quality slides, save your time and money, and give you your desired results.