The technology binds to the spike protein. In tests, it inhibited the infection capacity of Sars-CoV-2 by 93%.
Scientists at the University of California, in the United States, created nanosponges capable of neutralizing Sars-CoV-2, which causes Covid-19. The finding was published in the journal Nano Letters on Wednesday (17).
The researchers’ strategy was the following: as the new coronavirus first infect lung epithelial cells, they focused on developing nanoparticles capable of “deceiving” the microorganism. Therefore, the nanosponge consists of a polymer core covered by a cell membrane extracted from the lungs. This cover, in turn, has receptor proteins that Sars-CoV-2 uses to enter our cells.
According to the researchers, the technology binds to these proteins, making reproduction unfeasible and, therefore, containing infection by the new coronavirus. “Traditionally, drug developers for infectious diseases dive deep on the details of the pathogen in order to find druggable targets,” explained Liangfang Zhang, one of the researchers, in a statement. “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.”
The researchers prepared several different concentrations of nanosponges and tested them in cell cultures. According to them, at a concentration of 5 milligrams per milliliter, the technology inhibited the infection capacity of Sars-CoV-2 by 93%.
“From the perspective of an immunologist and virologist, the nanosponge platform was immediately appealing as a potential antiviral because of its ability to work against viruses of any kind,” said Anna Honko, co-author of the research. “This means that as opposed to a drug or antibody that might very specifically block SARS-CoV-2 infection or replication, these cell membrane nanosponges might function in a more holistic manner in treating a broad spectrum of viral infectious diseases.”
The technology has already proven to be safe in tests carried out on the respiratory tract and lungs of rats, but researchers will still evaluate the method’s effectiveness on other animals in the coming months. “Another interesting aspect of our approach is that even as SARS-CoV-2 mutates, as long as the virus can still invade the cells we are mimicking, our nanosponge approach should still work,” noted Zhang. “I’m not sure this can be said for some of the vaccines and therapeutics that are currently being developed.”
Scientists have also developed a version of the nanosponges covered by another type of cell, macrophages (white blood cells), which are part of the immune system. In tests, the technology was able to inhibit 88% of the infectious capacity of the new coronavirus.
The research team plans to study whether this version of the nanosponges can help contain the so-called cytokine storm, an exaggerated immune response that aggravates the condition of some patients with Covid-19. “We will see if the macrophage nanosponges can neutralize the excessive amount of these cytokines as well as neutralize the virus,” said Zhang.