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Microscope Slides Preparation

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Objects are magnified under compound microscopes are mounted onto microscope slides. Made from plastic or glass Slides measure approximately 1×3 inches in size and range from 1mm-1.2 millimeters thick.

Multiple preparation methods permit for advanced visualisation of organic and inorganic objects.

Flat and Concave Styles

  • One of the most fundamental microscopes slides are a rectangular flat piece made of soda lime glass plastic or borosilicate cover glass and has edges that are ground.
  • Each corner has a sharp 90-degrees. They, along with a rough edge, may result in minor cuts on fingers If not handled with care.
  • The bottom and/or top edges of a slide may be decorated with frosting, making it easy to mark the slide for identification of the sample or orientation. The etched frosting will keep the marks of the pen completely from the sample. A variety of frosted colors provide another method of categorizing.
  • Round safety corners to protect cuts that could be accidental, as also beveled edges that have cut corners that are ideal for blood sample slides are choices offered for both generic and frosted slides.
  • Concave microscope slides feature at least one or two surface depressions that are ideal for liquid solutions as well as larger specimens. These microscope slides that are more expensive are able to be used without cover.
  • Certain companies make plastic chambers that have a predetermined number of slides that have covers.
  • Flasks and wells that have been calibrated are easily viewed without having to prepare and clipping slides onto the microscope stage, which makes the process particularly beneficial in sediment research, for instance urine analysis. Additionally, some designs of tray can be put within an incubator or a refrigerator which allows for the examination of samples that have been cultured.

Additional Features

Certain tissues and cells are unable to adhere to a clear glass surface, and therefore require an electric charge or surface modification.


Save time and money, electrostatically charged slides are well-known option for scientists studying histology cell biology as well as the pathology.

The surface that are treated with biological reagents may create a slide that is water-proof and resistant to certain chemicals , and lessen the chances of cross-contamination. Other variations of microscope slides are:

Etched grid system or graticule

  • Researchers can keep track of and share information about the area(s) of concern to them.
  • Helps with hand sketching
  • Helps with the plotting of geographic areas
  • Estimated size and scale

Dual concavity

  • Comparative side-by-side analysis, including samples to control
  • Reduces the risk of cross-contamination

Transparent Mica

  • A rare substitute for glass
  • More resistant to dust, scratching
  • Reduces the glare

Cover Slips

  • The majority of them are made of silicate glass or borosilicate glass The coverslips are used to hold samples in place and shield them from accidental motion and contamination.
  • It also shields the microscope by preventing any direct interaction between specimen and the lens and accidental leakage of water-based substances.
  • The transparent, thin cover glass is generally square , and comes in two varieties Number 1 and Number 2.
  • Designed for high-resolution microscopy as well as preparations for oil immersion Number 1 covers come in .13-.17mm thick. Covers Number 2 are .17-.25 millimeters, designed for general use.
  • More uncommon characteristics are rectangular shapes, other materials like quartz and specific types of plastics as well as grids, etched lines and other thicknesses.
  • If you are not able to create an unavoidable slide using sealant or glue, coverslips are easily removed, sterilized and then re-used for multiple uses.

Preparation Techniques: Dry Mounts, Wet Mount, Squash, Staining

The most common methods for placing specimens on microscope slides include dry mount, wet mount as well as squash, smear, and staining.

Dry Mount

  • Dry mount is the most straightforward method to use: just place an uncut thin slice of the slide in the central portion of the slide. Then apply a cover slip to the specimen.
  • Dry mounts are great for studying hair feathers, feathers, and airborne particles, such as pollens and dust, as also dead material, such as legs of insects and aphids or antennae. Opaque specimens require very fine slices for adequate illumination.
  • Because they are utilized mostly for dead and inorganic matter, dry mounts may be expected to last for a long time.

Wet Mount

For aquatic samples as well as living organisms and natural studies Wet mounts allow you to suspend your specimens in fluids like brine, water, or immersion oil. Wet mounts require a liquid, pipette, tweezers and paper towels.

To make the slide ready:

  • Place a drop of liquid in the middle of the slide
  • Place the sample on the liquid with tweezers
  • From an angle put one end of the slip cover on the slide and make contact with the edge of the drop of liquid
  • Covers should be removed gradually, making sure to keep air bubbles out.
  • Get rid of any excess water using the paper towel

While wet mounts can be used to create a large variety of slides for microscopes, they also provide some sort of temporary window since the liquid dehydrates and living specimens die.

Organisms like protozoa could only survive for 30 minutes in a moist mount slide. Applying petroleum jelly on the outer edges of the cover slip forms an airtight seal that can extend the lifespan of the slide for some days.

Additionally larger protozoans like paramecium might be too big or move too fast in the conditions of the wet mount.

In these situations it is possible to add crushed pieces of glass cover in the water prior to the slip layer can create an additional space. Chemicals or cotton strands could be used to slow down the motion of amoeba, paramecium and ciliates.

Smear Slides

Smear slides need the use of two to three flat plain slides with cover slips, pipette, cover slips and tissue paper.

  • Pour a fluid sample, such as slime or blood onto slide
  • By using one of the edges on your second slide gradually smear the sample to create an even, thin coat
  • Place a cover slip on the sample, taking care not to catch air bubbles
  • Remove excess liquid

Ideally, smears must dry naturally within an environment that is moderate and steady in temperature.

The angle on the slide determines the size of the smear. A more steep angle results in a shorter smear. For blood samples Begin by inserting the slide with the sample, then move it across the slide and pull the blood away from the sample to form an even layer.

A larger slide could be made using two drops of blood, but only with blood from mammals, since erythrocytes don’t have nucleus that allows cells to accumulate in layers.

Squash Slides

For soft samples, squash slides are prepared by making the mount with water; then place lens tissue on top of the cover glass, then gentle press down, taking care not to break your sample, or crack the glass cover and then squeeze the sample. Remove any the excess water.


There are a variety of techniques to stain microscope slides including in vitro or non-vital staining of living cells, as well as vital or in vivo staining of living tissues. Staining creates contrast by using the color of the slide, which reveals the structural features that are not visible in other slides.

Staining solutions, such as Iodine, Methylene Blue and crystal violet may be applied to dry or wet mounts.

Simple staining technique:

  1. Apply one drop of staining solution onto the edges of one of the sides of the slip that covers the cover.
  2. Place the edge of a paper towel to the opposite side
  3. Let the dye run across the specimen

Stains can be particularly beneficial in the areas of histology, virology , and pathology and allow researchers to investigate and diagnose illnesses, as well as identify positive and negative bacteria and also examine the detailed features of a range of cells.

Prepared Slides

Particularly useful for education reasons and those who do not wish to go through the tedious process of making slides, pre-made microscope slides are accessible in all science fields and include:

  • Biology: Plants, Animals, Single-cell organisms
  • Human Anatomy: Organ samples, Tissues, Blood, Cells of the epithelium.
  • Botany: Monocot and dicot tissues
  • Zoology: Animal species from which samples are taken.
  • Marine-biology: Bacteria, Algae, Coral, Fish and Crustaceans
  • Pathology: Bacteria, Viral, Tissues that are diseased.

Microscope slides that have been prepared also provide access to marine life, animal tissues as well as diseased cells and other samples that might not be accessible for students or hobbyists.

Additionally, they can be used as a means of evaluating researchers and students to evaluate samples that have been collected.

Slides that have been prepared are bought by set sizes and are nearly always long-lasting, which allows for endless reuse.



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