Pathways to optical STED microscopy
Clausen, M. P., Galiani, S., De La Serna, J. B., Fritzsche, M., Chojnacki, J., Gehmlich, K., ... & Eggeling, C.
Optical far-field microscopy such as confocal fluorescence microscopy is a very popular technique for investigating the living cell. Unfortunately, its spatial resolution is limited to around 200 nm, impeding the imaging of small molecular assemblies. Recent decades have seen the development of optical nanoscopy, optical far-field microscopy with a spatial resolution down to molecular scales. STED microscopy was the first of such nanoscopy techniques. Despite the fact, that it in principle only requires the addition of a strong STED laser to a conventional microscope, STED nanoscopy was for a long time considered as a very complex technique, impossible to be applicable as a turn-key technique in everyday biological research. However, recent years has seen important improvements of the STED nanoscopy approach which have significantly simplified the setup. These developments mainly followed from optimization of fluorescent labels, laser technology and optical simplifications. As a result, STED microscopy setups have got more compact and have been realized on commercial instruments, allowing access to lessexperienced users in open imaging facilities. Here, we give a brief overview of the recent improvements in STED microscopy that made these important developments possible.