Single molecule microscopy of biomembranes (review)

Recent advances in the development of new microscopy techniques with a sens itivity of a single molecule have gained access to essentially new types of information obtainable from imaging biomolecular samples. These methodolog ies are analysed here in terms of their applicability to the in vivo visual ization of cellular processes on the molecular scale, in particular of proc esses in cell membranes. First examples of single molecule microscopy on ce ll membranes revealed new basic insight into the lateral organization of th e plasma membrane, providing the captivating perspective of an ultrasensiti ve methodology as a general tool to study local processes and heterogeneiti es in living cells.