Nanometer resolution imaging by single molecule switching.

The fluorescence intensity of single molecules can change dramatically even under constant laser excitation. The phenomenon is frequently called as ‘blinking,’ and involves molecules switching between high- and low-intensity states (1). In addition to spontaneous blinking, the fluorescence of some special fluorophores, such as cyanine dyes and photoactivatable fluorescent proteins, can be switched on and off, by choice, using a second laser. Recent single-molecule spectroscopy investigations have shed light on mechanisms of single-molecule blinking and photoswitching. This ability to controllably switch single molecules led to the invention of a novel fluorescence microscopy with nanometer spatial resolution well beyond the diffraction limit. (Published: 2 April 2010) Citation: Nano Reviews 2010, 1: 5122 - DOI: 10.3402/nano.v1i0.5122