Future coronavirus vaccines might harness nanoparticles
To carry the COVID-19 pandemic in order will depend not only on safe and effective vaccines but as well on the deployment of vast amounts of relatively cheap doses.
While vaccines predicated on mRNA, such as for example those produced by Pfizer and Moderna, are highly effective and quick to build up, they are expensive to create and must be stored at very low temperatures.
For the Pfizer vaccine, this entails storage area in a special freezer at a temperature between -80 and -60°C (-112 and -76°F).
Pfizer and Moderna as well advise that their respective vaccines are injected in two dosages several weeks apart to maximize their efficacy.
These factors present problems for low and middle income countries.
Conventional vaccines that derive from inactivated, weakened, or genetically altered viruses can be highly effective and so are better to store and transport.
However, they take a long time to develop and are more likely to reason side effects.
Biochemists in Stanford University, CA, experience created a good prototype of a good nanoparticle-based COVID-19 vaccine that they believe wouldn't normally only be cheap, safe, and effective but also remain stable at room temperature.
They are even hopeful that their vaccine could possibly be shipped and placed as a freeze-dried powder.
The scientists recently published the results of a preclinical study of the nanoparticle vaccine in the journal ACS Central Research.
“Our goal is to produce a single-shot vaccine that will not need a cold-chain for storage area or transportation,” says senior author Dr. Peter S. Kim, Virginia and D. K. Ludwig Professor of Biochemistry at Stanford. “The mark people for our vaccine can be low and middle class countries.”
The Stanford vaccine prospect is founded on nanoparticles of an iron-containing protein called ferritin. Each ferritin nanoparticle is normally studded with several of the spike proteins that the virus uses to penetrate its host cells.
Prior to the pandemic, Dr. Kim’s lab have been developing a ferritin-based vaccine against the Ebola virus.
Previous research suggests that vaccinating laboratory pets with nanoparticles decorated with viral proteins - which effectively mimic whole viruses - elicits a more robust immune response than injecting them with the isolated viral proteins.
When the pandemic struck, the biochemists swiftly adapted this approach to focus on SARS-CoV-2, the virus that triggers COVID-19.
First, they formulated a shortened version of the virus’ spike that's better to synthesize and employ. They bonded these shortened spikes to nanoparticles of ferritin, in that case employed electron microscopy to verify that they acquired the correct structure.
In mice, they compared the performance of the nanoparticle vaccine against four other vaccines:
- nanoparticles studded with full-length spikes
- full-length spikes alone
- shortened spikes alone
- the area of the spike that binds to host cells, referred to as the receptor binding domain