Writing Jia Yu Geng
Editor Wang Duoyu Typesetting Water Writing Since the outbreak of the epidemic, for each of us, the biggest change may be to wash hands frequently and disinfect items frequently
However, whether it is liquids (such as alcohol), gases (high-temperature steam), or ultraviolet radiation, long-term antibacterial resistance is impossible
to sanitize at once.
Metal surfaces based on copper and zinc can provide longer-lasting antimicrobial effects, but they often take several hours to kill bacteria
As we all know, in the struggle with microorganisms, human beings continue to experience the situation
of "the road is one foot high, and the devil is one foot high".
Although scientists have developed various preparations to destroy bacteria or viruses for nearly a century, and can kill more pathogens in less and less time, for the surface of the object, over time, annoying microorganisms, especially those that cause pathogens or viruses, will still "make a comeback"
Especially in public places, a large number of pathogens lurk on the surface of objects, and we can only "disinfect frequently at all times, so as not to cause trouble"
Therefore, there is an urgent need for a product that can resist germs
for a long time.
On August 24, 2022, researchers at the University of Michigan published a research paper
in the Journal Mater titled: Surfaces with instant and persistent antimicrobial efficacy against bacteria and SARS-CoV-2.
The study developed a safety coating with immediate and long-lasting broad-spectrum antibacterial or antiviral activity that can be sprayed on the surface of almost all objects, quickly killing various bacteria and viruses, and its antibacterial or antiviral potency can still reach 99.
at 6 months.
The team said the new coating promises to revolutionize
the way public places such as airports and hospitals are disinfected.
In the new study, the researchers chose a terpenoid present in tea tree oil and cinnamon oil as an antibacterial molecule
These compounds have been used as active antimicrobials against a wide range of pathogens for hundreds of years and have been approved by the FDA and the European Commission as food additives
Over the centuries, plants have evolved extraordinary survival strategies to fight off a large number of evolving viruses, bacteria, fungi, and insects
One such strategy is essential oils secreted on the surface of plant secondary metabolites, which can provide plants with broad-spectrum surface and air protection through a variety of mechanisms to defend against different pathogenic threats, including causing cell membranes to disintegrate and binding to proteins to inactivate
However, the extremely volatile nature of plant essential oils prevents them from achieving long-lasting defensive potency
So the team used polyurethane
This is a varnish-like sealant that is commonly used on surfaces
such as flooring and furniture.
But the key challenge remains, namely how to combine vegetable oils with polyurethanes to allow oil molecules to act as a bactericidal agent while preventing their rapid evaporation
They found that crosslinking could be solved by joining materials together
at the molecular level by heating.
Smaller oil molecules easily bind to cross-linked polymer molecules to form a stable matrix
But to kill bacteria, oil molecules need to penetrate the bacterial cell wall, which cannot be done if they are tightly bound in the matrix
Finally, the researchers found a compromise solution, that is, partially crosslinking these materials, allowing some oil molecules to function freely while allowing other oil molecules to bind tightly
The researchers say that while polyurethane is a safe and commonly used coating, they also conduct toxicity tests to ensure its safety and confirm that this particular combination of ingredients is even safer
than many current antimicrobials.
Through experiments, they found that only a part of the oil was crosslinked to have the desired effect
Free oil molecules tend to stay together with oil molecules that are cross-linked into the matrix, helping the coating to stay longer
Test results show that the new coating is fatal to a variety of epidemic viruses, E.
coli, methicillin-resistant Staphylococcus aureus (MRSA) and many other pathogens
It kills 99.
9 percent of the microbes, and even after months of repeated cleaning, abrasion, and other rough treatment of real-world surfaces like keyboards, cell phone screens, and cutting boards with chicken, the coating's bactericidal potency remains
Durability test results show that the coating can kill bacteria or viruses for up to 6 months or more before the essential oil begins to evaporate and reduce its antibacterial potency; Moreover, when the potency is weakened, the use of new oils to wipe the coating can exert a new round of antibacterial or antiviral effect
Study corresponding author Professor Anish Tuteja of the Department of Materials Science and Engineering at the University of Michigan said the team's goal was not just to develop a single-use coating, but to build a library
of basic material properties.
If these characteristics are fully understood, we can develop coatings
that meet the needs of a wide range of applications.
He also said the new technology is expected to be commercialized
within a year.
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