Steps of Preparing a Stained Biological Specimen for Microscopic Study

Steps of staining biological specimens vary greatly depending upon the type of staining techniques being applied. Some common steps in most of the staining techniques are given below:

• Wet Mounting: Wet mounting is the first step in simple vital staining technique where living cells are to be studied. It this step the specimen under study is placed in a drop of water on a glass slide.
• Fixation: Fixation involves treating the specimen with fixatives like formaldehyde and ethanol. This kills the specimen and maintains its structure by preventing decay.
• Embedding: Some cells and tissues needs embedding in suitable medium like paraffin wax to make sectioning easier.
• Deparaffinization: If embedding medium is used, deparaffinization is done using suitable solvent to remove the embedding medium.
• Staining: This step involves application of the stain to the specimen. Sometimes modarnts are added with stains in order to stain the unstainable specimen. Based on the staining techniques the further steps vary. It may involve washing, heating etc, followed by application of counterstain or other substances.
• Mounting: After staining is completed the specimen is mounted onto the slide with a suitable medium. Then a cover slip is placed on it. After mounting the specimen is ready for microscopic studies.

Staining in biology is a technique to apply chemical substances or dyes to a biological specimen to enhance the visibility and contrast of its cellular constituents under the microscope. Staining is classified into two types. They are vital and non-vital. Vital staining involves the application of non-toxic water-soluble stains to the living specimen to study them live. Whereas, non-vital staining is typical for dead tissues. Some common examples of stains include methylene blue, orcein, carmine, etc.