What precision-protein-tuning and nano-resolved single molecule sciences can do for each other.

While innovations in modern microscopy, spectroscopy, and nanoscopy techniques have made single molecule observation a standard in many laboratories, the actual design of meaningful fluorescence reporter systems now hinders major scientific breakthroughs. Even though the field of chemical biology is supercharging the fluorescence toolbox, surprisingly few strategies exist that make the transition from model systems to biologically relevant applications. At the same time, the number of microscopy techniques is growing dramatically. We explain our view on how the impact of modern technologies is influenced not only by further hard- and software developments, but also by the availability and suitability of protein-engineering tools. We identify how the largely independent research fields of chemical biology and fluorescence nanoscopy can influence each other to synergistically drive future technology that can visualize the localization, structure, and dynamics of molecular function without constraints.