Antibiotics were one of the most important inventions of the 20th century, but their effectiveness drops dramatically as bacteria develop resistance to them. Now researchers from the University of St. Louis have shown that ultra-short pulses of laser light can kill bacteria and viruses without damaging human cells.
The rise in multidrug-resistant "superbugs" is a looming health crisis that, according to some studies, could claim up to 10 million lives a year by 2050. Our last line of defense is already starting to malfunction, and some strains of bacteria are already resistant to all the antibiotics we use.
New antibiotics are constantly being developed, but this only partially solves the problem. To break the vicious circle, scientists are investigating other methods of killing bacteria that they cannot develop resistance to - physical attacks, such as special materials, synthetic polymers, molecular drills, liquid metal grinders, poisoned molecules and black phosphorus coatings.
And now lasers have been added to this list. Researchers have previously studied how ultra-short pulses of laser light can kill viruses and common bacteria, but in a new study, they looked at how well they can kill antibiotic-resistant bacteria as well as hard-to-kill bacterial spores.
The team focused on two specific types of superbugs: multi-drug resistant Staphylococcus aureus (MRSA) and E. coli, each representing one of two main categories of bacteria, gram-positive and gram-negative. They also targeted Bacillus cereus spores, which are foodborne pathogens that can survive cooking or cooking.
Indeed, laser pulses have killed over 99.9% of every type of bacteria. Scientists say the technique works because lasers excite protein structures within viruses and bacteria, causing some of their molecular bonds to break. Because the severed ends join in an almost random fashion, the function of the protein inside the microbe is shut down, killing them.
It is important to note that laser pulses do not harm human cells - scientists say they must be orders of magnitude more powerful before they become a threat to us. This could make them a safer, sanitizing alternative to harsh chemicals, radiation or heat.
"Ultrashort pulse laser technology uniquely inactivates pathogens while preserving human proteins and cells," says Show-Wei Tsen, the study's first author.
“Imagine if we could scan the site with a laser beam before closing a surgical wound and further reduce the chance of infection. I see that this technology will soon be used to disinfect biological products in vitro and even treat bloodstream infections in the future by putting patients on dialysis and passing blood through a laser treatment device. ”
The study was published in the Journal of Biophotonics.
PHOTO: Ultra-short laser pulses can kill viruses and antibiotic-resistant bacteria by destroying the proteins inside them. © Michael Whfull (Maria Samsonova)

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