Purpose of Microscope Staining

Most cells contain structures that are transparent and without color, which makes visualization difficult, even with the aid of a microscope. Cell staining is used to gain more information about cells and tissues, and allows for the structures within cells to be seen in great detail. Different types and methods of staining can be used to obtain the desired result.

History

• The first known cells stain was saffron, which was used to dye muscle fibers by Anton van Leeuwenhoek (the father of microscopy) in the late 1600s, allowing him to obtain more information about the structures of these cells. One of the most famous developments in cell staining was made in 1884 by Hans Christian Joachim Gram, who developed the method of gram staining to determine different types of cell walls in bacteria. Over time, more dyes have been developed that allow scientists to gain greater insight into the structure and function of cells.

Significance

• Cell staining can be used to answer a variety of interesting questions about cells and tissues. For example, cell staining can be used to determine if cells are dead or alive, which can be useful when viable cells are needed for a transplant or experimentation. Histological staining is commonly used in hospital laboratories to determine whether a tissue sample contains cancerous cells. In the research laboratory, it is common for scientists to use antibodies with fluorescent dyes to determine the specific location of a particular protein within cells.

Time Frame

• Depending on the type of staining being performed, a typical cell staining procedure can take anywhere from a couple of minutes to many hours. In addition to staining the cells, many times the membranes of the cells have to be altered in order for the stain to get inside (this process is called permeabilization). Also, many cells and tissues are fixed prior to or after staining so that the shape of the cells are preserved. Samples are also frequently mounted onto a microscope slide for analysis, which also takes time.

Considerations

• Cell staining is an acquired skill, and some complicated staining techniques, such as fluorescent stains that use antibodies, can take a number of trials before a consistent and reliable result can be obtained. As with any scientific experiment, appropriate controls should be used.

Expert Insight

• Today, cell staining can be used in combination with a number of different microscopes to study multiple variables at the same time. For example, scientists can visualize how two or more proteins interact inside a live cell using fluorescent cell staining and microscopy. Gold particles of varying sizes can be used to label different proteins so they can be studied with electron microscopy. Many times, different methods are used to support or refute a hypothesis.