US scientists design novel “trap” for COVID-19
Researchers at the Pritzker School of Molecular Engineering (PME) at the University of Chicago have come up with a novel way to trap SARS-CoV-2 viruses, the virus that causes COVID-19, within the body and then use the body’s own immune system to destroy it – using specially-designed “Nanotraps.”
In theory, these Nanotraps attract the virus by mimicking the target cells the virus infects; once bound the traps then sequester the virus from other cells and target it for destruction by the immune system. The researchers envision it could be administered via a nasal spray as a treatment for COVID-19, as well as a vaccine.
To design the Nanotrap, the research team looked into the mechanism SARS-CoV-2 uses to bind to cells, namely via a spike-like protein on its surface. The spike proteins easily bind to human cell’s ACE2 receptor proteins.
They then designed nanoparticles made of polymers and phospholipids, about 500 nanometers in diameter – much smaller than a cell. That means the Nanotraps can reach more areas inside the body and more effectively trap the virus.
These nanoparticles have a high density of ACE2 receptor proteins on their surface; the researchers also designed other nanoparticles with neutralising antibodies on their surfaces – by attaching ACE2 proteins and neutralising antibodies to nanoparticles, the researchers have created a robust system for trapping and eliminating the virus.
“Since the pandemic began, our research team has been developing this new way to treat COVID-19,” said Dr. Jun Huang, an assistant professor of molecular engineering whose lab led the research. “We have done rigorous testing to prove that these Nanotraps work, and we are excited about their potential.”
In testing, the researchers found no toxicity in a mouse model and deemed the system safe; while testing the Nanotraps against a pseudovirus – a less potent model of a virus that doesn’t replicate – in human lung cells in tissue culture plates completely blocked virus entry into the cells.
The researchers also tested the nanoparticles with a pseudovirus in an ex vivo lung perfusion system – a pair of donated lungs that is kept alive with a ventilator – and found that they completely blocked infection in the lungs.
The PME researchers also collaborated with researchers at Argonne National Laboratory to test the Nanotraps with a live virus (rather than a pseudovirus) in an in vitro system. They found that their system inhibited the virus 10 times better than neutralising antibodies or soluble ACE2 alone.
The Nanotraps are biodegradable and can be stored in a standard freezer. The researchers said the Nanotaps could ultimately be given via an intranasal spray, which would place them directly in the respiratory system and make them most effective; it is also possible to serve as a vaccine by optimising the Nanotrap formulation, creating an ultimate therapeutic system for the virus.
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