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ISRN Physical Chemistry
Volume 2012 (2012), Article ID 619251, 15 pages
http://dx.doi.org/10.5402/2012/619251
Review Article

Photoactivatable Fluorophores

Laboratory for Molecular Photonics, Department of Chemistry, University of Miami, 1301 Memorial Drive, Coral Gables, FL 33146-0431, USA

Received 25 July 2012; Accepted 16 August 2012

Academic Editors: H. Pal and M. Sliwa

Copyright © 2012 Françisco M. Raymo. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

Photoactivatable fluorophores switch from a nonemissive to an emissive state upon illumination at an activating wavelength and then emit after irradiation at an exciting wavelength. The interplay of such activation and excitation events can be exploited to switch fluorescence on in a defined region of space at a given interval of time. In turn, the spatiotemporal control of fluorescence translates into the opportunity to implement imaging and spectroscopic schemes that are not possible with conventional fluorophores. Specifically, photoactivatable fluorophores permit the monitoring of dynamic processes in real time as well as the reconstruction of images with subdiffraction resolution. These promising applications can have a significant impact on the characterization of the structures and functions of biomolecular systems. As a result, strategies to implement mechanisms for fluorescence photoactivation with synthetic fluorophores are particularly valuable. In fact, a number of versatile operating principles have already been identified to activate the fluorescence of numerous members of the main families of synthetic dyes. These methods are based on either the irreversible cleavage of covalent bonds or the reversible opening and closing of rings. This paper overviews the fundamental mechanisms that govern the behavior of these photoresponsive systems, illustrates structural designs for fluorescence photoactivation, and provides representative examples of photoactivatable fluorophores in actions.