Cell counting methods pdf

Image cytometry is the oldest cell counting methods pdf of cytometry. 1990s, the automation level of image cytometers has steadily increased. 1950s been the dominating cytometric device.

Flow cytometers operate by aligning single cells using flow techniques. To detect specific molecules when optically characterized, cells are in most cases stained with the same type of fluorochromes that are used by image cytometers. Flow cytometers generally provide less data than image cytometers, but have a significantly higher throughput. Cell sorters are flow cytometers capable of sorting cells according to their characteristics. The fluid stream is broken up into droplets by a mechanical vibration. The droplets are then electrically charged according to the characteristics of the cell contained within the droplet. Depending on their charge, the droplets are finally deflected by an electric field into different containers.

Conventional flow and image cytometers have the disadvantage of not being able to observe cells over time. After recording, the video is computer processed to track cytometric parameters over time. The early history of cytometry is closely associated with the development of the blood cell counting. Until the 1950s the hemocytometer was the standard method to count blood cells. However, the hemocytometer is still being used to count cells in cell culture laboratories. Successively the manual task of counting, using a microscope, is taken over by small automated image cytometers. Jena constructed the first ultraviolet microscope.

The intent of the microscope was to obtain higher optical resolution by using illumination with a shorter wavelength than visual light. Fortunately, Köhler saw the potential of fluorescence. By the early 1930s various firms manufactured ultraviolet fluorescent microscopes. The stage was set for cytometry to now go beyond the now established hemocytometer.