Scanning near-field optical microscopy in cell biology and microbiology.

Scanning a point light source in close proximity over a sample and recording the scattered or transmitted light intensity point by point allows one to record optical images with a resolution not limited by diffraction. An overview of this technique called scanning near-field optical microscopy (SNOM or NSOM) is given with emphasis on cell- and microbiology. After an introduction, where the basic features of the technique are explained, illustrative examples are presented, such as a HeLa cell, fluorescence labelled human chromosomes, super resolution fluorescence imaging, single molecule imaging and fluorescence resonance energy transfer between a single pair of dye molecules.