Heat fixation is a technique used in organism staining that is able to kill organisms, adhere them to the slides being used, and alter them so they can take on the stains being used. Fixing is a necessary step when performing a stain on a slide, explains Ohio State professor Stephen Abedon. Heat fixation is the most commonly used type of fixing for staining and studying organisms.
In biology, staining is the process used to help differentiate parts of a microscopic substance or organism on a slide. This is usually done by dying, or staining, parts of the organism or cell. By doing this, the contrast between different parts of the organism becomes more apparent and it is easier to identify and analyze the sample on the slide. Before an organism can be stained, it must be dead and fixed to the slide that goes under the microscope. After a slide has been prepared, it is exposed to intense heat. Usually this is done with some type of flame. This process kills the organism on the slide, and ensures it stays in place on the slide. For some types of organisms, the heat fixation even modifies the organisms or cells in such a way that they become more susceptible to being dyed. In other organisms, other types of staining techniques must be applied before the staining can begin.