Virus Traps
The "nanohubes" that absorb harmful pathogens and toxins were developed by engineers at the University of California at San Diego and tested by researchers from Boston University.
In laboratory experiments, nanocubes that mimicked lung cells and immune cells caused the SARS-CoV-2 virus to lose almost 90% of its invasiveness – the ability to penetrate the host cell and use its resources for replication and production of viral particles.
Nanocubes do not fight the virus itself, they are designed to protect healthy cells that the virus invades. In addition to encouraging data on the neutralization of the virus in cell culture, the researchers note that nanocubes covered with fragments of the outer membranes of macrophages may be able to absorb cytokines that cause a cytokine storm – the most dangerous aspect of COVID-19 infection.
Manufacturing and testing
Each nanocube consists of a polymer core covered with cell membranes extracted from type II lung epithelial cells or macrophages. The membranes cover the sponges with the same protein receptors as the cells they mimic – it is with these receptors that SARS-CoV-2 binds to penetrate the cells of the body.
In vitro researchers evaluated the ability of different concentrations of nanocubes to block the invasiveness of SARS-CoV-2. At a concentration of 5 milligrams per milliliter, nanoparticles coated with a lung cell membrane inhibited 93% of the invasiveness of SARS-CoV-2, sponges coated with macrophage receptors inhibited 88% of the invasiveness of SARS-CoV-2.
Over the next few months, researchers will evaluate the effectiveness of nanocubes in animal models. The group has already demonstrated their short-term safety in the respiratory tract and lungs of mice. When the nanocubes will be tested on humans depends on many factors, but the researchers are moving as fast as possible.
The authors note one important aspect of the new approach: nanocubes remain effective even when SARS-CoV-2 mutates. In other words, as long as the virus can penetrate into cells that mimic nanocubes, the method will work. The researchers also expect the nanocubes to be effective against other respiratory viruses, including those that could cause the next pandemic.
Mimicking lung epithelial cells and immune cells
Since the new coronavirus often infects lung epithelial cells as a first step, the researchers concluded that it would be advisable to mask the nanoparticle with fragments of the outer membranes of these cells to see if the virus could get trapped. Macrophages, which play a major role in inflammation, are also very active in the lungs during COVID-19 disease, so the second type of nanocubes was covered with macrophage membranes.
The research team plans to study whether macrophage sponges are also able to calm the cytokine storm in patients with COVID-19.
Potential COVID-19 therapy
The authors emphasize that COVID-19 nanocubes must undergo serious testing to prove safety and effectiveness in humans. But if the approach reaches clinical trials, there are several potential ways to deliver nanocubes, including direct injection into the lungs for intubated patients, by inhalation, similar to asthma medications or intravenously, especially for the treatment of cytokine storm.
A therapeutic dose will deliver a trillion or more nanocubes to the lungs, which will be able to divert the virus from healthy cells. As soon as the virus binds to the sponge, it loses viability and is no longer dangerous, it will be absorbed by immune cells.
Nanohubes also have the potential to prevent infection, as they can remain in the lung for some time.
Article by Q.Zhang et al. Cellular Nanosponges Inhibit SARS-CoV-2 Infection is published in the journal Nano Letters.
Aminat Adzhieva, portal "Eternal Youth" http://vechnayamolodost.ru According to UC San Diego news Center: Nanosponges Could Intercept Coronavirus Infection.