Azido Push-Pull Fluorogens Photoactivate to Produce Bright Fluorescent Labels

Dark azido push-pull chromophores have the ability to be photoactivated to produce bright fluorescent labels suitable for single-molecule imaging Upon illumination, the aryl azide functionality in the fluorogens participates in a photochemical conversion to an aryl amine thus restoring charge-transfer absorption and fluorescence Previously we reported that one compound DCDHF-V-P-azide was photoactivatable Here we demonstrate that the azide-to amine photoactivation process is generally applicable to a variety of push-pull chromophores, and we characterize the photophysical parameters including photoconversion quantum yield photostability and turn-on ratio Azido push-pull fluorogens provide a new class of photoactivatable single molecule probes for flourescent labeling and super-resolution microscopy Lastly we demonstrate that photoactivated push-pull dyes can insert into bonds of nearby biomolecules, simultaneously forming a covalent bond and becoming fluorescent (fluorogenic photoaffinity labeling)