What is meant by light scattering?
Light scattering measurements have found many applications in biology, ranging from the assessment of bacterial concentration in a suspension to resolution of the fine structure of the cell. Optical density measurement is a common method for the estimation of microbial biomass. When light interacts with a cell suspension some of that light is scattered out of the incident beam, while some is absorbed. The more concentrated the suspension, the more light is absorbed and scattered and thus biomass concentration can be estimated by measuring the amount of light that is transmitted through the suspension. As mentioned earlier, however, the special power of flow cytometry is its ability to make measurements on single cells rather than on populations of cells. When a single cell intersects the light beam of a flow cytometer some of the light is scattered out of the beam. The amount of light that is scattered by a cell is a complex function of its size, shape and refractive index. The sensiti
