Technology! Chinese scholars bring new expansion microscopy techniques

Thanks to innovations in expansion microscopy (ExM), we can see the inside of cells and other nanoscale structures
like never before.
These advances help provide future insights
into neuroscience, pathology, and many other biological and medical fields.

In the Jan.
2 paper, "Magnify is a universal molecular anchoring strategy for expansion microscopy," collaborators from Carnegie Mellon University, the University of Pittsburgh, and Brown University describe the new technique
known as "Magnify.
"

Leon Zhao, associate professor of biological sciences, said: "Magnify can be an effective and usable tool
in biotechnology.
"

Yongxin Zhao's biophotonics laboratory is a leader
in super-resolution imaging of biological samples through physical expansion of samples, known as expansion microscopy.
Through this process, the sample is embedded in an expandable hydrogel that expands uniformly to increase the distance between molecules, allowing them to be observed
at higher resolution.
This allows nanoscale biological structures previously only visible using expensive high-resolution imaging techniques to be seen
with standard microscopy tools.

Magnify is a variant of the expansion microscope that allows researchers to use a new hydrogel formulation invented by the team that preserves the spectrum of biomolecules, offers a wider range of applications in a variety of tissues, and increases the expansion rate linearly to 11 times or 1300 times
the original volume.

"We overcame some of the long-term challenges of expansion microscopy," says Yongxin Zhao, "and one of Magnify's main selling points is the general strategy
of preserving tissue biomolecules, including proteins, nuclear fragments, and carbohydrates, within the expanded sample.
" ”

Zhao Yongxin said it was important to keep the different biological components intact because previous protocols required eliminating many of the various biomolecules
that bind tissues together.
But these molecules may contain valuable information
for researchers.

"In the past, in the past, in order for cells to be really expandable, you needed enzymes to digest proteins, so in the end, you get an empty gel with a label that indicates the location of the
protein of interest," he said.
With this new method, molecules remain intact and multiple types of biomolecules
can be labeled in a single sample.

"Before, exams were like multiple-choice questions
.
If you want to label proteins, that's version one
.
If you want to label the nucleus, it will be a different version, and if you want to do synchronous imaging, it is difficult
.
Now with Magnify, you can select multiple items to label, such as proteins, lipids and carbohydrates, and image them together
.
”

Laboratory researcher Aleksandra Klimas, a postdoctoral researcher, said: "This is a convenient method
for imaging high-resolution specimens.
" "Traditionally, you need expensive equipment, specific reagents, and training
.
However, this method is widely applicable to many types of sample preparation and can be observed
with standard microscopes in biological laboratories.
”

Gallagher, who has a background in neuroscience, says the goal is to make these protocols as compatible as possible, so that researchers can benefit
from adopting Magnify as part of the toolkit.

"It works with different tissue types, fixing methods, and even tissues
that are preserved and stored.
It's very flexible because you don't necessarily need to redesign the experiment; It will work with
what you already have.
”

For researchers like Simon Watkins, founder and director of the University of Pittsburgh's Center for Bioimaging and the Pittsburgh Cancer Institute, the fact that the new protocol is compatible with a wide range of tissue types—including preserved tissue sections—is important
.
For example, most extended microscopy methods are optimized for brain tissue
.
In contrast, Magnify tested on samples from a variety of human organs and corresponding tumors, including the breast, brain, and colon
.

"Let's say you have a tissue with dense and non-dense components, which bypasses tissue
that previously didn't expand in equal amounts," Watkins said.
Leon has been working this issue to make this solution applicable to organizations
that have already archived.
”

Part of his research includes the study of movable cilia
that clear mucus in the body's trachea.
At 200 nanometers in diameter and only a few microns in length, these structures are
too small without time-consuming techniques such as electron microscopy.
Ren's team collaborated with Zhao's lab to develop and deliver a lung organoid model with ciliary ultrastructure and function-specific defects, validating Magnify's ability to
visualize clinically relevant cilia pathologies.

"With the latest magnification technology, we can expand these lung tissues and even see some of the ultrastructure of motor cilia with a normal microscope, which will speed up basic and clinical research
," he said.

The researchers were also able to observe defects
in cilia in patient-specific lung cells known to have genetic mutations.

"The lung tissue engineering community always needs a better way to describe the tissue systems we're studying," Ren said
.
This work is an important first step, and he hopes that the collaboration with Zhao's laboratory will be further refined and applied to the pathological samples
found in tissue banks.

Finally, the hydrogel developed by Zhao Labs for Magnify is stronger than its predecessor, which is very fragile and causes breaks
in the process.

"We want to develop this technology to make it more accessible to people
," he said.
"This goes in a different direction
.
There is a lot of interest
in using this tissue expansion technique for basic science.
”

Alison Barth, a professor of life sciences at Carnegie Mellon University
, studies synaptic connectivity during learning.
She said the wide range of applications offered by the new method would be a boon
for researchers.

"The brain is a good place to take advantage of these super-resolution techniques, and microscopy methods will benefit synaptic phenotyping and analysis
under different brain conditions.
"

"One of the main advances in this paper is the method's ability to work
on many different types of tissue specimens.
"