Why Dye a Cell for Miscopic Observation?

Viewing the inner structures and activities of cells can tell a physician or researcher a great deal about biological processes. White blood cells, for instance, must exist and reproduce in sufficient numbers to perform immune system functions, while other cell processes make life possible. Only through staining, the process of applying a dye to a cell sample, can people actually see these important structures and functions.

Cell Viewing Issues

• Scientists or doctors would not be able to see any detail inside most cells without first staining them. According to the Fun Science Gallery, all cells naturally appear transparent even under magnification. Red blood cells, for instance, appear barely visible as a result, and white blood cells become practically invisible. The inability to see cell structures clearly prompted Hans Christian Gram to invent, in 1882, the staining process as we know it in 2010, according to the University of Pennsylvania Health System.

Staining Benefits

• Biologists may use cell staining for a variety of applications. By viewing interior cell components, pathologists can detect anomalies associated with diseases. Students commonly view stained slides to gain a better understanding of cell structures, according to Microbial Life Education Resources. Staining can reveal how many cells still live in a given biological sample. Stained cells also give researchers a clear picture of the density of biological material, or biomass, within a particular environment.

Types of Stains

• Different types of stains or dyes reveal different parts or processes in cells. For instance, Microbial Life Education Resources states that a stain called Bismark Brown attaches to particular proteins called acid mucins, while carmine dyes cell starches red and crystal violet applies a purple coloring to cell walls. Other stains isolate particular types of cells, such as fuschsin's tendency to dye smooth cells. Some stains will work on both living and non-living cells, but only certain stains can safely color living cells with damaging them.

Methods

• Just as preparers must choose what type of stain best suits their purpose, they must also choose the right preparation method. All cells require mounting onto a slide either before or after staining. Living cells may actually grow onto the slide, while cells that must remain in "suspended animation" for future use require a process called fixation. Fixation employs chemicals that preserve the cell's chemical bonds. Preparers may pre-treat the cells with a surfactant to make them more receptive to the dyes, or they may add a compound called a mordant that helps the dye stick to the cell after rinsing the slide.

Considerations

• Using improper staining methods can defeat the entire purpose of staining a cell for observation. The Fun with Science Gallery warns that in some cases, applying a stain to an unprepared sample will disrupt the saline balance inside the cells, causing them to explode, spill their contents and produce an unusable sample. Fixing the sample in alcohol or another preservative before proceeding allows the cell walls to remain intact when they receive the stain.