How to Prepare a Microscope Slide

Preparing a microscope slide is one of the most interesting of all practical experiments. Students, after completing the experimental steps wait anxiously to view the results under the microscope because the final result that they observe under a microscope contributes a lot to their preliminary efforts.

Those who haven't performed this experiment earlier would find the content useful as we have explained you the process in details.

Before studying the subject matter, it's important for you to know the reason behind preparing a slide to observe it under a microscope. The common things that students view under a microscope are plant cells, bacterial shapes, stages of cell division and different types of structural tissues.

Preparing a slide means, staining and processing the sample to obtain a crystal clear view under a microscope. This further helps you in analyzing the characteristic properties of the samples and you can derive a logical conclusion for your experiment.

Slide preparation is also done at clinical and pathological labs for scrutinizing microbes and other types of pathogenic organisms.

So how to prepare microscope slides? Although, the process of preparing the slide depends on the aim of the experiment and the result that you want to achieve, there are a few steps that are common for all. The slide is also prepared according to the resolution of the microscope under which it will be viewed.

You will be provided with the sample and you should follow the instructions and precautions laid before by your teacher. Let's find out the basic steps for preparing a microscopic slide.

You will be provided with a thin piece of flat glass, which is known as microscopic slide, that must be cleaned before using. First rub your hand with a cotton dipped in ethanol. Then sterilize the slide by rubbing it with a cotton swab soaked in 70% alcohol.

Thoroughly clean the slide and then air dry it before placing the sample on it. Failing to clean the slide properly can give rise to false positive results.

There are basically three different ways to prepare the slide, viz. dry mount, wet mount and prepared mount. Structure of hair, feathers, dust particles and pollen grains are mounted dry while analysis of microorganisms and physiological liquids (blood, semen, urine, saliva, etc.) are done on wet mount.

Specific parts and intricate structures of samples are observed under prepared mount. We explain you the process in the following points.

★ In a dry mount, the specimen is simply placed on the slide and then a cover slip is directly placed on it. Sometimes, you need to heat fix the sample by heating the slide for a few seconds over a bunsen burner. You have to press the cover slip with your thumb for processing the sample properly.

★ In case of wet mount, you need to suspend the sample in water or any other liquid medium before viewing it under a microscope. Heat fixing glues it better on the slide, although it's not mandatory. Place a cover slip on the top of the sample and make sure that the liquid doesn't drop out. Now observe it under the lens.

★ Prepared mount technique is usually applied for analyzing the complex structures present in specific sections. The samples are cut into thin sections with the help of a microtome and then other steps follow.

A complete histological preparation is done by staining, dehydrating, fixing and treating it with different types of chemicals and solutions. The specimen is then attached firmly on the slide and then it is analyzed by setting the microscope under various resolutions.

Mounting media is the liquid that is applied on the specimen before covering it with a slip for the purpose of getting a clear resolution. The media should not react with the specimen and it should have a refractive index close to that of glass. The most common mounting media used for microscopic studies are Hoyer's mounting media and glycerol jelly.

Apply one or two drops on the sample with a dropper and then top the sample with the cover slip. Place the slide over the hole of the microscope stage and then adjust the light source.

Set the magnification (10X, 40X, 100X) value at a point that gives you the clearest image. You shall get a better hold on adjusting microscopes once you practice it twice or thrice.

Hope, you have completely understood how to prepare a microscope slide. We mention once again, that we have provided you an outline of the process here as the preparatory methods vary according to the type of specimen provided. Follow the procedures as explained in the given protocol to obtain accurate results and enjoy your practical sessions.