If you have an ACS member number, please enter it here so we can link this account to your membership. (optional)

ACS values your privacy. By submitting your information, you are gaining access to C&EN and subscribing to our weekly newsletter. We use the information you provide to make your reading experience better, and we will never sell your data to third party members.



Hybrid method boosts microscopy resolution

Combining expansion microscopy and STED improves resolution 30-fold relative to the diffraction limit

by Celia Henry Arnaud
May 7, 2018 | A version of this story appeared in Volume 96, Issue 19

An image of the cytoskeleton of a cell acquired with ExSTED, a hybrid of expansion microscopy and STED microscopy.
Credit: ACS Nano
ExSTED microscopy images microtubules in a cell. The color scale indicates the depth of various tubules in three-dimensional space.

Two methods are better than one, at least when it comes to improving resolution in microscopy. Stimulated emission depletion (STED) microscopy uses a doughnut-shaped laser beam to precisely control the location of fluorophore activation on a labeled sample. STED typically has resolution that is 10-fold better than diffraction-limited microscopy. In expansion microscopy, a fixed sample is embedded in a hydrogel, which swells and stretches the sample to four times its original size, leading to a physically generated improvement in resolution. Now, Alf Honigmann of the Max Planck Institute of Molecular Cell Biology & Genetics, Helge Ewers of Free University of Berlin, and coworkers report that ExSTED—the combination of the two methods—has 30-fold better resolution than diffraction-limited microscopy (ACS Nano 2018, DOI: 10.1021/acsnano.8b00776). The researchers used the hybrid method to image the microtubule network of cells in three dimensions. Because expanding the sample spreads out the fluorescent labels, the signal from any given area is greatly reduced. To counteract the signal reduction, the researchers used multiple antibodies to increase the number of fluorescent labels added to the microtubules. They hope to further improve the resolution by expanding samples a second time and finding ways of amplifying the fluorescence signal.


This article has been sent to the following recipient:

Chemistry matters. Join us to get the news you need.