Fluorescence (i.e. the emission of light from a electronically excited substance) is one of the most utilized physical phenomena in chemistry and biology. Though humans have been aware of fluorescence for thousands of years (e.g. fireflies), it wasn’t until the discovery of quinine in 1845 that we really started to understand its chemical basis(see figure above). Interestingly, during World War II, the study of quinine’s anti-malarial properties led to the development of the first spectrofluorometers which enabled true quantitative study of fluorescence. Finally, in the 1980-1990’s, new tools in synthetic chemistry and molecular biology allowed rational engineering of chemical fluorophores into a critical class of probes in biophysics(microscopy), molecular biology(sequencing), cell-biology(flow cytometry) and even anatomy (histology)).
