US researchers have created a molecule that can be used in an inhaler or nasal spray and claim it provides powerful protection against COVID-19.
The molecule – called AeroNabs – could change the course of the pandemic, the researchers say.
The molecule can be administered through an inhaler or nasal spray and could preclude the need to wear a mask or other personal protection equipment.
The University of California San Francisco (UCFS) scientists say the molecule could be offered cheaply and provide effective protection as an over-the-counter product.
“Far more effective than wearable forms of personal protective equipment, we think of AeroNabs as a molecular form of PPE that could serve as an important stop-gap until vaccines provide a more permanent solution to COVID-19,” said the co-inventor of AeroNabs Professor Peter Walter.
The molecule was ‘inspired’ by the antibody fragments that occur in llamas and camels and related animals.
It works by targeting the spikes on the coronavirus crown.
These spikes contain three receptor-binding domains (RBDs).
According to News Medical, “A receptor-binding domain (RBD) is a key part of a virus located on its ‘spike’ domain that allows it to dock to body receptors to gain entry into cells and lead to infection. These are also the primary targets in the prevention and treatment of viral infections, including SARS-CoV-2 – the virus that causes COVID-19.”
University of California, San Francisco researchers “believed that if they could find nanobodies that impede spike-ACE2 interactions, they could prevent the virus from infecting cells.”
So they created a synthetic version of a nanobody.
“The most potent of these nanobodies, however, not only acts as a sheath over RBDs, but also like a molecular mousetrap, clamping down on spikes in its closed, inactive state, which adds an additional layer of protection against the spike-ACE2 interactions that lead to infection,” said the researchers.
Co-inventor of AeroNabs Dr Aashish Manglik said that nanobodies work better than antibodies because they “offer a number of unique advantages for effective therapeutics against SARS-CoV-2”.
Nanobodies are easier to manipulate and modify in the lab and their relatively simple structure makes them significantly more stable than the antibodies of other mammals.
Nanobodies can also be easily and inexpensively mass-produced.
After screening more than two billion synthetic nanobodies, testing the most promising candidates and by screening them with stringent criteria, eliminating the weak or ineffective candidates, the researchers found 21 nanobodies that hindered COVID-19.
Further testing boiled those 21 down to three grand finalists that were “extraordinarily potent, preventing infection even at extremely low doses”.
The researchers then “put their nanobodies through a series of stress tests, subjecting them to high temperatures, turning them into a shelf-stable powder, and making an aerosol”.
Because the of the inherent stability of nanobodies, there was no loss of antiviral potency once the molecule was aerosolised.
Now, these molecules could effectively be self-administered with a nasal spray or inhaler.
Used once a day, say the co-creators, AeroNabs could provide reliable protection against SARS-CoV-2 until a vaccine becomes available.
Should further tests prove successful, AeroNabs could be widely available as an inexpensive medication and “a potent SARS-CoV-2 antiviral that could be practical to administer via a shelf-stable inhaler or nasal spray”.
“We’re not alone in thinking that AeroNabs are a remarkable technology,” said Dr Manglik.
“If AeroNabs prove as effective as we anticipate, they may help reshape the course of the pandemic worldwide.”
Would you trust a tested inhaler or nasal spray over a mask?
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