Staining Types

Staining Types

Staining Types, Staining: A stain is a substance that adheres to cells giving the cell color. Staining is a Process in which cells of the tissue are colored with a positive stain chemical dye for identification. Most biological Structures are colorless and Transparent so staining is applied to see better contrast.

Types of Staining Techniques:

Simple staining (use of single stain)Differential staining (uses of two contrasting Stains Separated by a decolorizing agent)
For visualization of (Morphological shape and arrangement)Identification — Special Stain
Gram StainAcid-fast Stain for Stain Spores stain for Capsules Stains for flagella stain for the metachromatic granules

Difference between Simple and Differential Staining of bacteria:

Simple Staining:

Simple staining is one step method using only one dye. Simple staining uses only one reagent and is used to determine the shape, arrangement of microbial, and dimensions.

Differential Staining:

Differential Staining is a Staining Process that uses more than one staining chemical reagents dye to different cellular structures.


Terms of ComparisionSimple StainingDifferential Staining
No. of Stain usedSize, shape, and arrangement of bacterial cellsUses more than one Stain
Color impartingImparts only one color to bacterial cellsImparts two or more different color to bacterial cells
OutcomeImparts two or more different colors to bacterial cellsSize shape and
arrangement; Differentiation in groups.
Identification of Structures of bacteria cells.
Examples•Methylene blue
•Crystal violet Staining
• Malachite green
• Basic fuchsin staining
• Safranine staining
Gram staining
• Acid-fast staining
• Endospore staining
Procedure1- Take a clean grease free slide
2- Prepare Smean on it
3- Air dry and heat fix
flood the slide with Stain
4- Allow the stain to react for 2 mint
5- Wash the slide with water
6- Analysis through a microscope examine to look for objective
1 Take a clean grease free slide
2-Applying a Primary stain (crystal violet)
3-Adding a mordant (Gram’s iodine)
4-Rapid decolorization with ethanol, acetone, or a mixture of both
5- Counterstaining with Safranin
Crystal violet Staining. G+ve
Gram staining
Endospore staining
Staining Types

Difference between Invivo and Invitro Staining:

Invitro staining:

In Invitro staining involves coloring cells or structures that have been removed from their biological context.

Invivo Staining:

Invivo means “in life” (as contrasted to in-vitro staining). Invivo staining is the Process of dyeing living tissue.

Staining Types


Terms of ComparisionIn-vivo StainingInvitro Staining
Type of SpecimenLiving biologicalDead or non-living
Types of stainSpedmen: Vital stains areBiological specimen Non-vital stains
FixationUsed: No need to fixAre used fixation is required
OutcomeReveal cytological details cell or structure:
Its form (morphology) or Position within a cell or tissue. Reveal sites where specific chemical reactions are taking place within cells
Size Shape and arrangement:
Differentiates between groups:
Identify structurs
ExamplesJanus Green Staining
Trypan blue staining
Gram staining
ObservationDead cell live cell
Trypan blue staining
Gram staining

Difference between Positive staining and Negative staining:

Positive Staining:

It is also called direct staining. The negatively, charged cell wall of many micro-organisms attracts
the Positively charged chromophore, which causes the specimen to absorb the stain giving it the color of the stain being used.

Negative Staining:

it is also called indirect staining. In which bacterial cells are not stained but are made visible against a dark background. Acidic is used in this staining. Acidic staining is a negative charge, therefore it does not fix with the negative charge bacterial cell. On the other hand, it forms deposits around the cell, resulting in the appearance of bacterial cell clusters.

Staining Types


Terms of ComparisionPositive Staining (Direct)Negative Staining(Indirect)
Stain usedBasic StainAcidic stain
Also known asDirect stainIndirect staining
Charge of Stain Examples• Positive charge
• Methylene blue Crystal violet
• Malachite green
• Negative charge
• Nigrosine
• India ink
• Eosin, Cong red
Heat fixation outcomeRequired Stains the barterial cellsNot required stains the background
PrincipleWhen a Staining Prundare colors the cells present In a Prepration, but leaves the background colarless (appearing as white)Negative staining requires the use of an acidic stain. Acidic stain with its negativly changed choumigen. will not Penetrate the cells because they have negative charge on bacterial Surface.
Colored bacterial cell
Colorless bacterial cell
Procedure1- The Procedure of positive Staining first step is sterilize the inoculation loop over the flame of bunsen burner and Cool it down for a 2-3 mnt.
2- Seundiinent step dip it in a broth containing bacteria and take loop full of culture.
3- Third step smear a culture on glass slide and make a thin film and allow the Suspension to completely dry.
4- Quickly pass the slide over a flame 3-4 times to heat fix.
5- let it cool it down for a bit Place it over a staining tray cover this entire thin film with the stain for a few minute.
Dry it and observe the result
1- Place a small nigrosin close to one end of a clean slide.
2- Using aseptic technique, place teofull of inoculum from the bacterial culture in the drop of nigrosin 4 min.
3- ) Place a slide against the drop of suspended organism at 45°C angle and allow the drop to Spread along the slide.
4- Push the Slide away from the drop of suspended to form a thin smear. Air dry.
Do not heat fix the Slide.

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