To humans, soap often evokes feelings of lightness and calm. But in the world of microorganisms, soap molecules are really murderous and raging.
Legend has it that a rain that fell on Earth several thousand years ago swept away the fat and ashes of the sacrificed creatures. When this mixture drifts into a nearby river, they mix together and form sparkling bubbles that can wash away skin and clothes.
Soap appeared from there, becoming an invention that changed human history.
But perhaps, even our ancestors at that time could hardly imagine that these fragile, sparkling bubbles of all colors would become a powerful weapon to help people fight the germs. invisible diseases in the future.
To humans, soap often evokes feelings of lightness and calm. But in the world of microorganisms, soap molecules are a real killer and raging. A single drop of soap diluted in water is enough to destroy many types of bacteria and viruses, including the new corona virus that is causing the current Covid-19 epidemic.
The secret of soap, lies in the very way it is born from ash and fat.
When you look at the chemical nature of soap, you will see that it has two parts. One is the molecules at the hydrophilic, base-containing ends. The remainder is the tail of a long chain of hydrophobic fatty acids. Bases (found in ash) have combined with fatty acids (found in fats) in a reaction called saponification.
As the name suggests, the hydrophilic end of soap likes to cling to water molecules. Whereas, hydrophobic tails will avoid water and prefer to stick to oils or fats. Soap molecules, when suspended in water, will clump together, turn our hydrophilic heads apart and hit hydrophobic tails into tiny balls called micelles.
Some bacteria and viruses have lipid membranes that resemble bilayer micelles. They have two hydrophobic tail bands sandwiched between the two hydrophilic ends. These membranes serve as scaffolding for important proteins to attach to their surfaces, allowing viruses to enter cells and cause disease.
Pathogens encapsulated in lipids include coronaviruses, HIV, viral strains of hepatitis B and C, herpes, Ebola, Zika, dengue fever, and many bacteria that attack the intestines and respiratory tract.
When you wash your hands with soap and water, you are attacking viruses and bacteria with soap molecules. The hydrophobic tails of the soap will try to evade the water molecule. And in the process, they will penetrate the lipid membranes of bacteria or viruses, and then separate them.
"Soap molecules act like crowbars, destabilizing the entire [pathogen's outer membrane] system," said Professor Pall Thordarson, Head of the Department of Chemistry at the University of New South Wales. The lipid membranes are dislodged by levers from the soap molecule, releasing their essential proteins and the bacteria die.
Whereas with viruses like corona, soap molecules dislodge the lipid membrane, where they attach infectious spikes to them. When the corona's thorns are removed, they will no longer be able to infect human cells. The virus is then said to be inactivated.
Simultaneously with this destructive process, some soap molecules will break the chemical bonds that allow bacteria, viruses and dirt to stick to the surface of the skin, knocking them out of your hands.
Micelles can also form around particles of dirt and debris from viruses and bacteria, encapsulating them in floating cages. So that when you flush, all microorganisms that have been destroyed, trapped or inactivated will drift down the drain.
In general, hand sanitizer is not as reliable as soap. Although alcohols above 60% can act like soap to destroy and destabilize the lipid membranes of bacteria or viruses, they cannot form micelles that help wash microorganisms away from the skin.
In addition, there are many strains of viruses that do not contain lipid membranes, as well as bacteria that have an external protein shield. These pathogens include bacteria that cause meningitis, pneumonia, diarrhea, and skin infections, as well as hepatitis A, polio, rhinoviruses, and adenoviruses (which cause the common cold) that cannot be killed or damaged. activated with alcohol-based hand sanitizer.
Germs that are highly resistant to soap, even if not killed, will be washed away when you rub your hands well. That's why washing hands with soap and water is often recommended as a better hygiene measure than using hand sanitizer.
From the ashes and fat of sacrificial creatures drifting into a nearby river, to the age of gene therapy and robotic surgery, soap's recipe has remained essentially unchanged. Soap remains effective after thousands of years, unlike antibiotics, which become resistant to bacteria every few years.
Throughout history, soap remains one of the most valuable medical interventions we have at our disposal. Hand washing with soap and water is also one of the public health measures that greatly reduces the pandemic rate and limits the number of infections, preventing overcrowding in hospitals and clinics.
But this method only works if people wash their hands often and thoroughly: Apply soap evenly over the entire palm, rub for at least 20 seconds, to every finger, between the fingers, the back of the hand, palms and nail crevices…
During the raging Covid-19 pandemic, soap is not only a weapon to protect you personally from pathogens, but also an important public health measure, to create a common safety net. for the whole society.
If everyone were to wash their hands often, there would be fewer Covid-19 patients. The disease will therefore spread more slowly, more people will be protected.
As you can see, on a molecular level, soap works by breaking things down, but on a social level, it helps keep everything together.
Remember this the next time you wash your hands: because someone else's life could be in your own hands.
Nguồn: Tri Thức Trẻ
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