Photoactivatable synthetic fluorophores.

Photoactivatable fluorophores switch from a nonemissive state to an emissive one under irradiation at an activation wavelength and then emit light in the form of fluorescence upon illumination at an excitation wavelength. Such a concatenation of activation and excitation events translates into the possibility of switching fluorescence on within a defined region of space at a given interval of time. In turn, the spatiotemporal control of fluorescence offers the opportunity to monitor dynamic processes in real time as well as to reconstruct images with resolution at the nanometer level. As a result, these photoresponsive molecular switches are becoming invaluable analytical tools to probe the structures and dynamics of a diversity of materials relying on the noninvasive character of fluorescence imaging.