Chemiluminescence bioluminescence

For many years, due to the availability and low cost of radioisotope-labeled secondary antibodies, radioactive detection was the method of choice in Western blotting. Newer methods that are less hazardous and easier to use, while maintaining comparable sensitivity, have been developed. Today, Western blotting detection methods can be light-based, (chemiluminescence, bioluminescence, chemifluorescence, and fluorescence), radioactivity-based, or color-based. It is important to note that the detection sensitivity depends on the affinity of the primary antibody for the antigen and on the affinity of the secondary antibody for the primary antibody and can therefore vary considerably from one protein sample to another and from one antibody batch to another. 

Other types of luminescence are defined by the source of the energy that causes the light emission. These include chemiluminescence, bioluminescence, electroluminescence, sonoluminescence, triboluminescence, and thermoluminescence. 

Chemiluminescence, bioluminescence, and electrochemiluminescence are types of luminescence in which the excitation event is caused by a chemical, biochemical, or electrochemical reaction and not by photoillumination. 

Kricka U, Park JY (2011) Miniaturized analytical devices based on chemiluminescence, bioluminescence... 

Luminescence is generally less intense than incandescence, but it often emanates from extremely small amounts of matter, which has beneficial implications for analytical science. Nevertheless, the utilization of luminescence for analysis is quite a recent innovation. The following commentary describes the fundamental spectroscopic and chemical principles underlying luminescence in relation to its application in analytical science. As other articles will deal with atomic spectroscopy, this discussion will be restricted to analytical molecular luminescence spectroscopy including fluorescence, phosphorescence, and chemiluminescence (bioluminescence being a special case of chemiluminescence). 

---