Improved Illumination Achieved Via Superresolution Microscope Design

JAKE SALTZMAN, NEWS EDITOR
jake.saltzman@photonics.com

By increasing the uniformity of light dispersed across the field of view, a team of biophysicists from the Laboratory of Experimental Biophysics (LEB) at École Polytechnique Federale de Lausanne has successfully increased the size of images it can capture using a superresolution fluorescence microscope.

The biophysicists relied on the enhanced technology to capture detailed images of the twists found within centrioles. Cells contain a pair of centrioles, the organelle responsible for segregating chromosomes during cell division.

Through the design of its high-throughput superresolution microscope that uses light to probe specimens, the team was able to observe centrioles while they were still inside living cells.

Centrioles are 1000× smaller than a human hair. Though researchers already use electron microscopy to know their physical structure, the intricate code of post-translational modifications (PTMs) of which centrioles are composed had previously been invisible to electron microscopes.

In the design, an intricate alignment of mirrors and lenses delivers laser light into a specimen under observation. The team paired the setup with advanced sample preparation; using physical magnification of the sample and fluorophores, the team was able to make proteins reemit light.

The results provided an uncommonly detailed look at the nanoscale structures, isolated as well as in situ. An examination confirmed that centrioles possess a ridged, bullet-like shape. The team found that a single PTM twists around a centriole’s ridges, despite a high degree of organization.

“Our study underlines that [superresolution] microscopy is an important partner to electron microscopy for structural biology,” said Suliana Manley, a biophysicist who leads the LEB.

Beyond its application to centriole observation, scientists could potentially use the new technology to study additional structures inside and/or from cells, as well as to look at multimolecular machines, such as viruses.

The research was published in Nature Methods (www.doi.org/10.1038/s41592-020-0859-z).