Hyo-Jick
Choi, a professor in the University of Alberta Department of Chemical and
Materials Engineering, noticed that many people wear a simple surgical-style
mask for protection during outbreaks of influenza or other potentially deadly
viruses such as severe acute respiratory syndrome (SARS) or Middle East
respiratory syndrome (MERS).
Trouble
is, the masks weren't designed to prevent the spread of viruses.
"Surgical
masks were originally designed to protect the wearer from infectious droplets
in clinical settings, but it doesn't help much to prevent the spread of
respiratory diseases such as SARS or MERS or influenza," says Choi.
Airborne
pathogens like influenza are transmitted in aerosol droplets when we cough or
sneeze. The masks may well trap the virus-laden droplets but the virus is still
infectious on the mask. Merely handling the mask opens up
new avenues for infection. Even respirators designed to protect individuals
from viral aerosols have the same shortcoming -- viruses trapped in respirators
still pose risks for infection and transmission.
Masks
capable of killing viruses would save lives, especially in an epidemic or
pandemic situation. During the 2014-2015 season nearly 8,000 Canadians were
hospitalized with the flu. That same year, deaths related to influenza in
Canada reached an all-time high of nearly 600.
Knowing
that the masks are inexpensive and commonly used, Choi and his research team
went about exploring ways to improve the mask's filter. And this is where a
problem he is struggling with in one field of research -- the development of
oral vaccines like a pill or a lozenge -- became a solution in another area.
A
major hurdle in the development of oral vaccines is that when liquid solutions
dry, crystals form and destroy the virus used in vaccines, rendering the
treatment useless. In a nifty bit of engineering judo, Choi flipped the problem
on its head and turned crystallization into a bug buster, using it as a tool to
kill active viruses.
Choi
and his team developed a salt formulation and applied it to the filters, in the
hope that salt crystals would "deactivate" the influenza virus.
The
mechanics of simple chemistry make the treatment work. When an aerosol droplet
carrying the influenza virus contacts the treated filter, the droplet absorbs
salt on the filter. The virus is exposed to continually increasing
concentrations of salt. As the droplet evaporates, the virus suffers fatal
physical damage when the salt returns to its crystalized state.
While
developing solid vaccines, Choi observed that sugar used for stabilizing the
vaccine during the drying process crystalizes as it dries out. When crystals
form, sharp edges and spikes take shape and they physically destroy the virus
vaccine.
"We
realized that we could use that to our advantage to improve surgical
masks," said Choi.
In
a series of experiments and tests at the University of Alberta and in the
Department of Medical Zoology at the Kyung Hee University School of Medicine in
Seoul, South Korea, the team arrived at a perfect treatment that improves the
efficacy of the fibre filter inside the masks.
By
using a safe substance (table salt) to improve an existing, approved product,
Choi sees very few roadblocks to implementing the innovation.
For
further details see:
Posted by Dr. Tim Sandle
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