Mussels' underwater glue inspires synthetic cement
Researchers use nature's strongest secrets to build even stronger
biomaterials
Date:
March 3, 2022
Source:
Northwestern University
Summary:
Researchers have used a novel method to replicate mussel-adhesive
proteins, creating a stronger glue than the material they set out
to mimic.
FULL STORY ========================================================================== Those who have tried to pry a mussel from anything from wood to rock
know how stubborn the underwater mollusks are -- and their gluey secret
has long captivated scientists. For years, researchers have attempted
to replicate the extraordinary adhesive and its properties in the lab, targeting some of the eight proteins that mussels secrete and use to
coat an organ called a foot that mussels use to attach to surfaces.
==========================================================================
Now, using a novel method to arrange molecules, researchers at
Northwestern University have created a material that performs even
better than the glue they were trying to mimic. Their findings, to
be published March 3 in the Journal of the American Chemical Society,
expand on how these protein-like polymers can be used as a platform to
create new materials and therapeutics.
"The polymer could be used as an adhesive in a biomedical context,
which means now you could stick it to a specific tissue in the body,"
said Northwestern's Nathan Gianneschi. "And keep other molecules
nearby in one place, which would be useful in wound healing or repair." Gianneschi led the study and is the Jacob and Rosaline Cohn Professor
of Chemistry in the Weinberg College of Arts and Sciences at Northwestern.
Proteins like those secreted by mussel feet exist around nature. Evolution
has made a habit of creating these long, linear chains of amino acids that repeat over and over (called tandem repeat proteins, or TRPs). Appearing
at times stretchy, strong and sticky, the protein frameworks show up in
insect wings and legs, spider silk and mussel feet. Scientists know the
exact primary sequences of amino acids that make up many such proteins,
yet have trouble replicating the complicated natural process while still maintaining the extraordinary qualities.
The paper's first author Or Berger, a postdoctoral researcher in
Gianneschi's lab who studies peptides -- these very chains of amino
acids -- came with an idea for how to arrange amino acid building blocks differently to replicate the properties rather than directly copy the
structure of mussel proteins.
==========================================================================
By taking the building block of one of the proteins (the repeat
decapeptide, a 10-amino acid sequence that makes up the mussel foot
protein), and plugging it into synthetic polymer, Berger thought the
properties may be enhanced.
As associate director of the International Institute for Nanotechnology, Gianneschi has built much of his lab around the idea of mimicking proteins
in function by using polymer chemistry. Within precision therapeutics,
drug therapies like antibodies and other small molecules combat some
diseases, where a nanocarrier is used to deliver a drug to a target more effectively. But Gianneschi says replicating proteins could approach
biological problems differently, by changing interactions inside and
between cells that are involved in the progression of disease, or between cells, tissues and materials.
"Proteins arrange amino acids as chains, but instead we took them and
arranged them in parallel, on a dense synthetic polymer backbone,"
Gianneschi said.
"This was the same thing we have begun to do for controlling specific biological interactions, so the same platform technology we will use
for future therapeutics has really become potentially interesting in
materials science." The result was something that looks like a brush of peptides rather than looping together amino acids in a straight line as a chain. While the novel process may seem like adding an additional step,
forming protein-like polymers (PLPs) skips several steps, requiring
researchers to form peptides in a readily available synthesizer and
insert them into the tightly packed backbone rather than going through
tedious steps of protein expression.
To test the new material's efficacy, the researchers applied either
the polymer material or the native mussel protein to glass plates. The researchers placed cells on the plates and then, after washing them,
assessed how many cells were present, either attached or not, to gauge
how well the materials performed.
They found the PLP formed a cellular superglue, leaving the most cells
attached compared to the native mixture and untreated plate.
==========================================================================
"We actually didn't mean to improve on the mussel's properties,"
Berger said.
"We only meant to mimic it, but when we went and tested it in several
different assays, we actually got better properties than the native
material in these settings." The team hopes the model can be widely
applicable across other proteins that repeat their sequence to gain
function in a new way to replicate proteins. They hypothesize such a
platform could perform better than their native counterparts because
they are denser and scalable. Gianneschi said this is the first of many
papers to discuss polymer-based protein mimics, and he is already thinking about applications for future materials.
Resilin, for example, a stretchy protein found in insect legs and wings,
could be used to make flexible drones and other robotics.
"When you talk about polymers, some people immediately think of
plastic bags and bottles," said Gianneschi said. "Instead, these
are very functional, advanced precision materials, made accessible."
Gianneschi and Berger are inventors on pending intellectual property in
this space. Gianneschi also is a professor of biomedical engineering
and materials science and engineering in the McCormick School of
Engineering and a member of the Chemistry of Life Processes Institute,
Simpson Querrey Institute and Robert H. Lurie Comprehensive Cancer
Center of Northwestern University. He is the co- founder of a company,
Grove Biopharma, that seeks to develop versions of these materials as translational therapeutics.
========================================================================== Story Source: Materials provided by Northwestern_University. Original
written by Win Reynolds. Note: Content may be edited for style and length.
========================================================================== Journal Reference:
1. Or Berger, Claudia Battistella, Yusu Chen, Julia Oktawiec, Zofia E.
Siwicka, Danielle Tullman-Ercek, Muzhou Wang, Nathan C. Gianneschi.
Mussel Adhesive-Inspired Proteomimetic Polymer. Journal of the
American Chemical Society, 2022; DOI: 10.1021/jacs.1c10936 ==========================================================================
Link to news story:
https://www.sciencedaily.com/releases/2022/03/220303112236.htm
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