Fulgimides as Light-Activated Tools in Biological Investigations

With high spatiotemporal control, the conformation, rigidity and electronics of photoresponsive bioactive molecules can be altered. This, in turn, allows for control over the biological properties of these molecules. Incorporation of a photoswitchable moiety into a number of reported inhibitors, ligands and modulators has demonstrated the ability to modulate enzyme, receptor and ion channel responses using light. To date, the major classes of photoswitches explored in biological applications have been the azobenzenes and diarylethenes. Even though the use of these photoswitches has established the value of photoresponsive molecules as biological tools, several limitations have become apparent. Fulgimides represent a promising class of photoswitches that are not widely used for such biological purposes. Their properties are similar to that of diarylethenes, as their photochromism is based on a 6 pi-electrocyclic rearrangement, however, fulgimides have the added advantage of thermal stability for both isomers. Fulgimides exhibit high photostationary states and fatigue resistance, with the ability to switch in aqueous buffer solutions. In this minireview, these advantageous photophysical properties will be discussed, as well as the use of fulgimides in biological investigations.