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The Contribution of Plastics
In the Treatment Of COVID -19 Patients
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Ajay D Padsalgikar, PhD
DSM Biomedical
Exton, PA, USA |
The world is in the middle of an
unprecedented and serious pandemic with close to 10
million people infected worldwide and almost 0.5 million
deaths. The virus causing this pandemic is the novel
corona virus termed as covid-19 or corona virus disease
2019. While the exact origin of the virus is still not
clear, however, the impact that it has had on the health
of the world population and the debilitating effect on
world economy is very visible. The role of plastics in the
medical sector has come to the forefront in the
prevention, testing and treatment of covid-19. This
article goes through a background of the disease and
importance of medical plastics in every step of the way.
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Coronavirus
The coronavirus, like all
viruses, is a parasite which can only reproduce within
cells. Thus, they are very different from bacteria and
fungi, which are self-reproducing. Coronaviruses observed
high magnifications, for e.g. in the electron microscope,
display a “crown-like” appearance is hence termed ‘corona’
which is Latin for crown.
Coronavirus use RNA molecules to encode their
genes, as do influenza viruses, HIV, and rhinoviruses (common
cold). The coronavirus particles are organized with long RNA
polymers tightly packed into the center of the particle, and
surrounded by a protective capsid, which is a lattice of
repeated protein molecules referred to as coat or capsid
proteins. In coronavirus, these proteins are called
nucleocapsid (N). The coronavirus core particle is further
surrounded by an outer membrane envelope made of lipids (fats)
with proteins inserted. These membranes derive from the cells
in which the virus was last assembled but are modified to
contain specific viral proteins, including the spike (S),
membrane (M), and envelope (E) proteins.
 As
seen in Figure 1, coronaviruses are roughly spherical
particles with bulging surface projections. The dimensions of
the virus are extremely small and the virus is only visible
under very high magnifications, the average diameter of the
virus particles is around 125 nanometers (nm, 0.125 µm). The
diameter of the envelope is 85 nm and the spikes are 20 nm
long.
Figure 1. Structure of the Coronavirus
Coronavirus particles can be rapidly
inactivated by exposure to different liquids, 70% ethanol or
90% isopropanol (rubbing alcohol), hydrogen peroxide
solutions, hypochlorite bleach, soaps and detergents, as well
as by UV light and the high temperatures of cooking.
Prevention
The most effective technique to fight
coronavirus transmission, as espoused by all authorities
around the world, has been an emphasis on frequent hand
washing with soap, keeping a distance of around six feet
between individuals and the use of masks. There are also
certain preventive steps that need to be practiced by medical
personnel, that includes the use of personal protective
equipment or PPE. The PPE includes respirator masks, facial
shields, gloves and gowns.
Masks
Masks are classified according to the level of
particle filtration they can offer. The higher filtration
level masks, N95, are used by medical personnel as a part of
their PPE. The N95 masks can be detailed as follows:
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N: This is a Respirator Rating Letter Class.
It stands for “Non-Oil” meaning that if no oil-based
particulates are present, then you can use the mask in the
work environment. Other masks ratings are R (resistant to oil
for 8 hours) and P (oil proof).
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95: Masks ending in a 95, have a 95 percent
efficiency. Masks ending in a 99 have a 99 percent efficiency.
Masks ending in 100 are 99.97 percent efficient and that is
the same as a HEPA quality filter.
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3 microns: The masks filter out contaminants
like dusts, mists and fumes. The minimum size of .3 microns of
particulates and large droplets won’t pass through the
barrier.
N95 respirators are made from non-woven fibers,
usually polypropylene, the structure of these fibers within
the mask make them act as efficient filters. Particles get
trapped as they are travel through the dense network of the
material’s fibers. The fibers are generally thinner than a
strand of hair and can be about a micron in diameter.
The N95 mask is constructed through multiple
layers of nonwoven fabric. There are two outward protective
layers of the fabric created using spun bonding and melt
blowing. The process of spun bonding involves the delivery of
a polymer melt into nozzles similar to melt spinning process.
As the melt exits the nozzle, with the quenching, air flow and
calendaring, different polymer strands are bonded with each
other and deposited on a conveyor belt. Melt blowing is a
process similar to spun bonding, in which multiple machine
nozzles use air to spray threads of melted synthetic polymers
onto a conveyor. The outer layers use spun bonding whereas the
inner high filtration layer use melt blowing to create a finer
mesh. The filter is made of thousands of nonwoven fibers, each
thinner than a strand of hair and fused together.
Figure 2. N95 (left) and surgical (right) mask
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