Intramolecular triplet-state quenching as a general method for photostabilization

Optical microscopy is an established method to visualize small objects such as cells, viruses, or even smaller entities such as single (bio)molecules. To visualize these objects, light emitting molecules, so-called fluorophores, are linked to the system of interest. Their emission is observed and directly probes the system of interest. Occasional transits to chemically reactive and non-fluorescent states, though, results in an unstable emission and short observation periods. To prevent these transients or irreversible signal losses, so-called photostabilizers are added that depopulate the reactive non-fluorescent states. Signal duration and quality are both greatly increased via this approach. The addition of these photostabilizers is, however, not compatible with living biological systems due to their toxicity or interference with the biological structure. This thesis presents a new approach to link photostabilizers synthetically to the fluorophore on the biomolecule. The approach allows using intramolecular photostabilization of various classes of fluorophores with different types of photostabilizers. With this technique, no addition of photostabilizers is required and a significant increase in stability could be achieved. This general concept uses unnatural amino acids as a platform to link fluorophore, photostabilizer and biomolecule. We are convinced that the strategy described here will promote intramolecular photostabilization to become the new gold standard for photostabilization.