Potential Nanoparticle Treatment for COVID-19

May 25 2020

To this day, COVID-19 remains to be a very real threat. Scientists all over the world are working hand-in-hand to combat it, and a recent development from a team led by German researchers found a promising avenue of treatment for the disease.

Viruses like SARS-CoV-2, which causes COVID-19, rely on spike proteins on their surfaces to infect host cells. The spike proteins bind to receptors on the surface of the target cells, allowing the virus to enter. As an analogy, consider a lock-and-key mechanism. The viral spike proteins are like keys that fit well into the locks (receptors) in the target cells. The cells would then ‘open’ and let the viruses in. 

To further help viruses infect host cells, they take advantage of a principle known as multivalent binding. This is when several spike proteins bind to several receptors at the same time. With that, viruses can more successfully enter host cells.

A possible solution, then, would be to block the viral spike proteins so that they cannot access the target cells’ receptors. That is exactly what Daniel Lauster and a team of 27 researchers developed, published in the journal Nature Nanotechnology

Lauster and his team synthesised nanoparticles that adhere to the spike proteins of influenza A virus, effectively preventing it from entering host cells. Images captured via cryo-electron tomography revealed that the nanoparticles completely encapsulated the viruses. Effectively, the viruses are barred from entering the host.

The nanoparticles were based on bacterial phage capsids, which are made from modified parts of another type of virus called bacteriophages. These viruses infect bacteria only, so they are harmless to animals and humans. The phage capsids were customised so that they bind to haemagglutinin (HA), which is a common spike protein in influenza A. The geometry of the capsids was also arranged in a manner that maximises multivalent interactions with HA. Results indicated that influenza A could no longer replicate once the hosts are treated with the phage capsids.

Furthermore, the nanoparticles were found to be non-toxic and non-immunogenic, meaning they do not elicit an allergic reaction or any abnormal response from the immune system. This would make it a good candidate for human trials later on.

Based on the results of the study, it can be said that nanoparticles offer a promising treatment for influenza A. With this, modifying the phage capsids can theoretically allow them to also envelop SARS-CoV-2 particles, making it a promising potential avenue for treatment of COVID-19.

 

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