The irruption of the coronavirus pandemic a little over a year ago has been a real revolution in the world not only in health, but in science itself, since never before have so many efforts been made to fight a new virus, nor had so many companies, scientists and governments mobilized at the same time.
Thus, while dozens of scientific studies on SARS-CoV-2 and COVID-19 (the disease caused by the virus) were published every day, before the end of 2020 the first vaccines were approved.
But there is still a long way to go to end the pandemic, and while the planned vaccination plan continues with the aim of achieving herd immunity as soon as possible, we continue to hear studies and research that may shed even more light on the matter.
Thus, we have learned that researchers from the Pritzker School of Molecular Engineering (PME) of the University of Chicago, in the United States, have designed a completely new potential treatment for COVID-19, based on nanoparticles capable of capturing SARS-CoV- 2 inside the body . And then use your own immune system to destroy it .
These nanoparticles attract the virus by mimicking the target cells, which are the cells that the virus infects. When the virus binds to these nanoparticles, they are capable of hijacking the virus from other cells and attacking it, in order for the immune system to destroy it.
In theory, these nanoparticles could also be used in variants of the virus, which would almost certainly lead to a potential new way of inhibiting the virus in the future.
Although the therapy is still in the early stages, scientists believe it could be administered by nasal spray as a form of treatment for COVID-19.
Designing the perfect trap
To design these nanoparticles, the researchers conducted rigorous tests to show that they work. To do this, they examined the mechanism that SARS-CoV-2 uses to bind to cells: a spike-shaped protein, located on its surface, that binds to an ACE2 receptor protein in the human cell.
To create a trap capable of binding the virus in the same way, the researchers designed nanoparticles with a high density of ACE2 proteins on their surface , in addition to other nanoparticles with neutralizing antibodies on their surfaces, which are created inside the human body when someone is infected.
Although the idea is not new, since both ACE2 proteins and neutralizing antibodies have been used in treatments for COVID-19, it is new to join them to nanoparticles, thanks to which a much more robust system has been created, capable of catch and remove the virus .
These nanoparticles, made of polymers and phospholipids, are around 500 nanometers in diameter, being considerably smaller than a cell. And this is really positive, since it means that the nanoparticles can reach more areas inside the body, trapping the virus more effectively.
The scientists tested the safety of the system in a mouse model, and found no toxicity . They then tested the nanoparticles against a pseudovirus, which is a less potent model of a virus that does not replicate, in human lung cells in tissue culture dishes. And they found that they could completely block entry into cells.
Once the pseudovirus attached itself to the nanoparticles (which happened just 10 minutes after injection), they used a molecule that calls on macrophages in the body to engulf and degrade the nanoparticles. Thus, 48 hours later, the nanoparticles cleared and degraded.
A possible future treatment
Scientists hope to continue testing the system, including further testing with live viruses and, above all, on the different SARS-CoV-2 variants found so far.
Since these nanoparticles can be easily modulated, it is possible to modify different proteins or antibodies, or to target different immune cells, depending on what is needed with the new variants.
They can then be stored in a standard freezer and, finally, they could be administered through an intranasal spray, which would offer the advantage of placing them directly into the respiratory system, making them even more effective.
In addition, the scientists also confirm that, by optimizing the formulation, it would be possible to convert the treatment into a vaccine, developing a definitive therapeutic system for the virus .
