Fluctuation correlation spectroscopy in cells. Determination of molecular aggregation

The determination of molecular interactions in cells has become a field of great interest in the post-genomic era. Ideally, we will like to know which protein is interacting with which, the migration and the localization of the proteins in the cell. During the past years very powerful optical methods have been developed that have the sensitivity to detect single molecules and molecular interactions. Although most of these methods have been demonstrated in solutions or on molecules immobilized on a surface, we will like to extend this methodology to the cell environment. Fluctuation correlation spectroscopy has been proposed as a method to detect single molecules, determine some of the chemico-physical parameters such as local diffusion and molecular brightness. Finally, advances in the determination of spatio-temporal correlations in a cell will be discussed.