Transcriber: Eunice Tan Reviewer: Tanya Cushman
In these modern times,
we're growing increasingly used to
healthcare advances happening at lightning speed,
and that's thanks to world-leading researchers across the globe,
including at Queen's University Belfast.
However, the recent coronavirus crisis
has really highlighted how much time, effort, energy, and expertise
goes into identifying and developing cures and, importantly, vaccines
for these particularly virulent pathogens and diseases.
Of course, whilst we're waiting on the development of a cure and a vaccine,
and as things stand at the minute,
that could be at least a year or more away,
we've been issued with guidance both at a government and local level
that's aimed at helping us to remain safe
and to reduce the spread of this very dangerous infection.
Of course, as time's moved on,
we've seen the modification,
relaxation,
and in some countries, removal of that guidance,
including lockdown measures.
And at this point in time,
we are not a hundred percent sure of the effect that that will have
on the infection and mortality rate related to this disease.
Throughout this crisis,
under various different types of guidance that we've been given, however,
one piece of guidance has remained consistent:
to ensure that you regularly, thoroughly, and correctly
wash your hands with soap and water.
And this guidance seems quite simple and straightforward.
How can simple soap and water
help to defeat this virus and to keep our population safe?
To start to think about this a little bit more,
it's going to be important to think about what soap is
and how it actually works
before we start to think about it in the context of the coronavirus.
[Surfactants]
In chemistry,
we refer to soap molecules as being 'surfactants',
or surface active agents.
And whilst this sounds like quite a complicated term,
all it really means
is that soap and surfactants can really have a major effect
in terms of how different things stick to one another,
how their surfaces interact.
And that's, of course,
the basis of how soap helps us to do things like clean our skin
and things within the likes of our kitchens and bathrooms as well.
To understand that a little bit more,
it's important to look at the structure of soap, or a surfactant,
because that will help us to understand
the basis of how these particular substances work.
Here we can see a very straightforward representation
of a surfactant molecule structure.
And what we can see here
is that there are two main parts to the molecule:
a hydrophilic head that really likes interacting with water
and a hydrophobic tail that really doesn't like water at all.
So if we start to put these surfactants into some water,
they will try and arrange themselves so that they're as happy as possible,
with the bits that like water being in contact with it
and the bits that don't being as far away from it as possible.
So let's think about trying to clean something with soap.
We have some dirt on a surface, and water,
and we add some soap to that situation.
What happens over time
is that the hydrophobic tails want to get away from water,
and they form what we call 'micelles'.
And micelles are essentially little bubbles of surfactant
that have all of the hydrophobic tails pointing inwards
so that they're as far away from the water as possible,
with the hydrophilic heads pointing outwards
in contact with the water.
When we do this in reality
and we're cleaning something like our hands, for example,
pieces of dirt will be trapped within these micelles.
And that means that these pieces of dirt are trapped within these bubbles
that have an outer layer that likes being in contact with water.
And as such, as we continue to wash our hands, for example,
those pieces of dirt are carried away by the flow of the water over our hands.
So now that we understand a little bit more about how soap works,
let's start to think about the coronavirus itself -
have a look at its biochemical structure,
find out more about how it works.
And in doing so,
we'll get a really big clue about how soap can help us to defeat this infection.
The SARS-CoV-2 virus, which is the cause of COVID-19,
shares its structure with a range of other viruses.
The simplified structure that we can see here
shows two main areas within the virus's structure.
One of these, the lipid bilayer, is the most important part
in terms of how soap can be used to defeat this virus.
And this lipid bilayer
is made of molecules that are very similar to those that we've seen already -
molecules that contain a hydrophilic head that likes water
and hydrophobic tails that really don't like water much at all.
In the case of this virus,
these molecules arrange themselves in this double or bilayer,
with the hydrophobic tails facing in
and the hydrophilic heads facing out into water.
As a result, we end up with this thick layer,
the middle of which is hydrophobic and contains very little water,
and the outside of the virus then coming into contact with water
as a result of those hydrophilic heads.
If we then introduce water and our soap into the system then,
we know that our soap, our surfactant molecules,
have those hydrophobic tails,
and they're constantly searching
for an area that contains very little water.
Luckily for us,
we know that the inside, the innermost part of this lipid bilayer,
is hydrophobic and contains very little water.
And as we continue to wash our hands and use soap,
the surfactant molecules try to locate their hydrophobic tails
into this area that contains very little water.
As the process continues,
our surfactant molecules will do their job
and continue to form micelles,
as we've seen before.
This time,
rather than the micelles circling around a piece of dirt that might be on our skin,
they circle around a certain number of molecules within the lipid bilayer,
within the viral coat.
As the process continues then,
the micelle is carried away
by the action of the water that we're using to wash our hands,
and that leaves a gap in that lipid bilayer.
That, of course, is a problem for the virus
because it's got a massive hole in its surface now -
a lot like popping a balloon -
and that then allows very important processes to occur,
like the removal of the viral replication machinery.
That then means that our virus particle is no longer viable,
can no longer replicate
and no longer cause the disease and the symptoms
that we're all very aware of.
So that's how soap can help us to defeat the coronavirus.
In recent times,
we've seen a lot and heard a lot about the use of hand sanitiser as well,
even hearing stories of people stockpiling supplies
to ensure that they have enough
to last them throughout this entire crisis.
Hand sanitiser is, of course, very effective.
But it misses out a few of the key important points
that soap and water provides us,
one of the main ones being the action of the soap and the water together
to carry away all of those pathogens
and the particular particles that they break up into,
away from our skin and down into the drain.
And that's a very critical, important point.
So what does this all mean for us, then?
We should ensure
that we continue to wash our hands correctly, thoroughly, and often,
and when we can't do that,
to make sure that we use a product like a hand sanitiser
to try and minimise the amount of the virus that we're exposed to,
reduce the spread,
and keep everyone safe.