‘Nanosponges’ act as a Decoy for the New Coronavirus-COVID-19
‘Nanosponges’ act as a Decoy for the New Coronavirus-COVID-19
A new study
has found that nanosponges — tiny, bio-friendly plastics coated in lung and
immune cell membranes — act as a decoy for SARS-CoV-2, neutralizing the virus.
A team of
scientists has found that a new technology is effective at distracting and
neutralizing SARS-CoV-2 in a laboratory setting.
The
research, published in the journal Nano
Letters, has implications not only for treating SARS-CoV-2 but also for
other virulent viruses, such as influenza, Ebola, Marburg, and Lassa viruses.
COVID-19 Therapies
As the initial
wave of the COVID-19 pandemic eases in some countries, attention is turning to
therapies that may be of use in slowing the spread of the virus, reducing the
risk of infection or saving the lives of people in intensive care.
In the
absence of a vaccine — which could not be available for years, if at all — treatments and therapies that help reduce
the negative effects of the pandemic are crucial.
In this
context, lab results from researchers at Boston University’s National Emerging
Infectious Diseases Laboratories (NEIDL) and the University of California, San
Diego seem promising.
The
researchers have made use of new technology to see whether SARS-CoV-2 can be
drawn to nanoparticles that neutralize the virus.
Prof. Anna
Honko, a NEIDL microbiologist and co-first author of the study, comments on the
findings.
“I was
skeptical at the beginning because it seemed too good to be true. But when I saw
the first set of results in the lab, I was just astonished.”
– Prof. Anna
Honko
The
technology works by creating microscopic, bio-friendly polymers, which are then
coated in cells from living lung tissue or the immune system.
“It looks
like a nanoparticle coated in pieces of cell membrane,” says Prof. Honko. “The
small polymer [droplet] mimics a cell having a membrane around it.”
SARS-CoV-2
is attracted to lung cell membranes. After attaching to the outside of the
cell, the virus gains entry and uses the cell’s internal machinery to replicate
itself. These new virus particles then exit the cell to continue the cycle
of spreading and multiplying.
However, the
researchers found that the polymers coated in lung cells did a better job of
attracting the virus than the lung cells themselves.
According to
Prof. Anthony Griffiths, a NEIDL microbiologist and co-corresponding author of
the study, “Our guess is that it acts like a decoy, it competes with cells for
the virus.”
“They are
little bits of plastic, just containing the outer pieces of cells with none of
the internal cellular machinery contained inside living cells. Conceptually,
it’s such a simple idea. It mops up the virus like a sponge.”
As a
consequence, the researchers have named the polymers “nanosponges.”
Once
SARS-CoV-2 attaches to the nanosponges rather than lung cells, the virus
quickly dies.
The
researchers believe that if nanosponges were administered to the body, the
immune system would clear away the dead cell debris, which is one of its key
jobs.
As well as
distracting and neutralizing SARS-CoV-2, the nanosponges were effective at
reducing inflammation, the researchers found.
This is
important, as the rapid spread of inflammation is central to severe cases of
COVID-19 and can be a key factor in death from the illness.
Nanosponges
covered in immune cells, the team discovered, “soak up” signals that increase
inflammation.
For this
reason, a combination of nanosponges — some covered in lung cells, some in
immune cells — could both neutralize SARS-CoV-2 and treat the body’s reaction
to COVID-19.
Profs. Honko
and Griffiths now intend to treat animals infected with a coronavirus using
their new method, working closely with colleagues at the University of
California, San Diego, who originally developed the technology. Their aim is to
create a treatment that is safe and effective for humans.
According to
Prof. Liangfang Zhang, a nanoengineer and leader of the California-based team,
“Traditionally, drug developers for infectious diseases dive deep on the
details of the pathogen in order to find druggable targets.”
“Our
approach is different. We only need to know what the target cells are. And
then, we aim to protect the targets by creating biomimetic decoys.”
After the
emergence of SARS-CoV-2, Prof. Zhang realized that his technology could play a
role in treating the disease. He reached out to NEIDL for help with
implementing the technology in response to the pandemic.
The
researchers believe that it should be possible to create nanosponges that can be
implemented in humans. According to Prof. Griffiths, “We should be able to drop
it right into the nose. In humans, it could be something like a nasal spray.”
“That would
be an easy and safe administration method that should target the appropriate
[respiratory] tissues,” agrees Prof. Honko. “And if you wanted to treat
patients that are already intubated, you could deliver it straight into the
lung.”
The
treatment could also be repurposed to treat other viruses that are resistant to
conventional treatments, or for which no effective vaccine has been found.
By changing
the type of cell membranes covering the polymers, other viruses could be
attracted to these, rather than human cells.
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