Cells, which are essential for the living and functioning of organisms, are fundamental units of life. Microscopy is required to investigate cells and their inner structures because they are too small to be observed clearly by the naked eye. Yet, the diffraction limit of light sets a barrier at ~200 nm for us to look in more detail. Super-resolution microscopy is a profound advancement in microscopic techniques to break this limit and helps us visualize targets of interest down to 5-nm optical resolution.

The cover image of the March 9 issue of Biophysical Reports is a super-resolved image of the microtubules in HEK293T cells. Microtubules are major components of the cytoskeleton in eukaryotic cells. The appearance of their structure indicates a range of biological implications, e.g., the phase of the cell cycle and development of Alzheimer’s disease. Microtubules can be visualized by dye labeling. In our case, we used a dye-labeled antibody. This dye, Alexa Fluor 647, can fluoresce. More importantly, it can be photo-switched, in other words, turned “on” and “off,” in a reducing and oxidizing buffer system under the microscope. Because the photo-switching events in this imaging technique, dSTORM, are stochastic, the fluorescence of single molecules can be recorded one at a time. These single localizations will then be computationally fitted to result in a super-resolved image of the dye-labeled structure with spatial resolution that can reach down to 5 nm. This allows us to break the diffraction limit and resolve fine cellular structures, in this case, the microtubules. We therefore can obtain more information on the targets of interest, e.g., the size and structure, which can potentially help us understand and interpret the mechanisms of many biological events.

Through our study and this cover, we highlight how the advancement of optical instruments can set a standard for high-quality imaging, at low cost, with very easy implementation. We therefore expect its quick adoption across academia, and industry could conceivably recruit more scientists to super-resolve the structure of living organisms and other targets of interest. This could guide us to understand the mechanisms of a range of biological processes and thus extend our lifespan.

If you are interested in finding out more on how we use super-resolution microscopy to study a range of diseases, such as cancers and neurodegenerative diseases, please visit https://www.klenermangroup.co.uk/.

- Jeff Lam, Yunzhao Wu, Eleni Dimou, Ziwei Zhang, Matthew Cheetham, Markus Körbel, Zengjie Xia, David Klenerman, and John Danial