Friday, June 06, 2008

When some molecules are exposed to the correct wavelength of light they are excited to a higher state, the molecule then drops back down to a normal state and emits light at a lower wavelength. This emission of light, Fluorescence, is a powerful detection tool. Under the right conditions single molecules can even be detected. In an immunoassay an antibody to a protein being studied has a fluorescent molecule attached to it. When the antibodies attach to the protein and are exposed to the correct wavelength of light the whole protein-antibody complex fluoresces and is detected at a very low level. In fluorescence microscopy the specificity of the antibodies makes it possible to study one protein in many different cells or tissues. Using optical filters the only thing the researcher sees through the microscope is the protein of interest.