TABLE OF CONTENTS Several biomolecules involved both in the metabolic processes and in the histological organization of cells and tissues are characterized by fluorescence properties that can be exploited to obtain information on the morpho-functional conditions of the biological substrate, suitable for diagnostic applications.
An overview of the endogenous fluorophores responsible for the autofluorescence is given concerning the photophysical properties and their dependence on the evolution of the biological condition of cells and tissues.
Most of the components of the biological material under excitation at suitable wavelength give rise to a fluorescence emission covering the UV-near-IR spectral range. This emission is called "autofluorescence", or "primary fluorescence" or "light-induced fluorescence" (LIF), to be distinguished from the "induced fluorescence" that is obtained upon labelling the structures under investigation by means of exogenous fluorochromes.
Autofluorescence was the first form of fluorescence to be investigated by microscopy, and was reviewed in detail by Haitinger in 1938 [ [1]]. Autofluorescence is generally much more intense in biological material belonging to the vegetable kingdom than to that of the animals. In fact, plant tissues naturally contain a large variety of fluorochromes that, for their spectral features and quantum efficiency, find wide application as exogenous markers in analytical cytofluorometry. Substances such as quinone, coumarin, cyanine, tetrapyrrole derivatives and many alkaloids are commercially extracted...
