Combining expansion microscopy and super-resolution microscopy for imaging beyond the diffraction limit

Abstract Expansion microscopy has over the past decade developed into an accessible and affordable microscopy method capable of reaching tens of nanometer effective resolution in a diverse range of application areas, all with conventional microscopy. In the meanwhile, super-resolution microscopy has continued its development towards single-nanometer resolution. With one being a sample preparation technique, and the other an optical technique, it did not take long until combined approaches were suggested. Here, we review the development of these combined methods from initial ideas and implementations, through protocol optimization, and towards application areas. We further list practical considerations applicable when choosing to implement and optimize these methods. The emphasis lies on the expansion protocol adaptations necessary to meet the diverse demands of the optical imaging applied.