Researchers have developed an entirely new treatment for COVID: ‘Nanotraps’ that capture the viruses inside the body, allowing the immune systems to destroy them
The “Nanotraps” mimick the human cells the virus normally attaches to, and bind it to their surface, keeping the virus from reaching other cells and target it for destruction by the immune system. It is possible that Nanotraps could be used on SARS-CoV-2 variants, and could be administered as a nasal spray.
“Since the pandemic began, our research team has been developing this new way to treat COVID-19,” said Assistant Professor Jun Huang, whose lab led the research. “We have done rigorous testing to prove that these Nanotraps work, and we are excited about their potential.”
Postdoc Min Chen and graduate student Jill Rosenberg targeted the spike mechanism that SARS-CoV-2 uses to lock onto ACE2 proteins on human cells.
To create a trap that would bind to the virus in the same way, they designed nanoparticles with a high density of ACE2 proteins on their surface. Other nanoparticles were designed with neutralising antibodies on their surfaces.
ACE2 proteins and neutralising antibodies have both been used in COVID treatments, but by mounting them onto nanoparticles, a much more effective and robust means for trapping the virus was created.
The nanoparticles are smaller than cells, 500 nanometres in diameter, allowing them to reach deep inside tissue and trap the virus.
No evidence of toxicity was seen in tests with mice, and they then tested the Nanotraps against a non-replicating virus called a pseudovirus in human lung cells in tissue culture plates and saw that they completely prevented viral entry into the cells.
When the nanoparticle binds to the virus (about 10 minutes after injection), it chemically signalled macrophages to engulf and destroy the nanoparticle and the attached virus. Macrophages normally engulf nanoparticles, so this merely sped up the process.
Testing the Nanotraps on a pair of donated lungs kept alive with a ventilator, they found that they completely prevented infection.
They 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 a 10 times better performance than with neutralising antibodies or ACE2 inhibitor.
The researchers plan further tests, including live virus and its variants.
“That’s what is so powerful about this Nanotrap,” Rosenberg said. “It’s easily modulated. We can switch out different antibodies or proteins or target different immune cells, based on what we need with new variants.”
Storage is simple, as the Nanotraps can be kept in a standard freezer, and administration is simple, using a nasal spray. The researchers said it is also possible to serve as a vaccine by optimisation of the Nanotrap formulation.
Source: Phys.Org
Journal information: Min Chen et al, Nanotraps for the containment and clearance of SARS-CoV-2, Matter (2021). DOI: 10.1016/j.matt.2021.04.005
