Nanoantibiotic
"Armed" oxygen destroys superbugs
Evgenia Efimova, Vesti
There is no doubt that antibiotics are saving the world from deadly infections today, but, unfortunately, this line of defense of humanity is increasingly weakening. This is due to the intensive use of antibiotics for several decades. In order to prevent a future in which once routine medical procedures will again become life-threatening, it is necessary to develop new ways to combat bacteria that quickly develop resistance to antibiotics available in the arsenal of doctors. A recent study has shown that oxygen, special nanoparticles and light can be used against them.
If the problem is left without due attention, experts suggest that in the future superbugs can cause up to 10 million deaths per year.
Specialists are developing new antibiotics, but they will eventually lose their power, as bacteria continue to adjust their genomes to "new needs". Some scientists, not wanting to participate in what they consider to be a fruitless "arms race," turn to technologies to which bacteria will never be able to develop resistance, and create new surfaces and special lighting. The former will not allow colonies of pathogenic microorganisms to gain a foothold and, accordingly, grow, and light will destroy even the most resilient bacteria.
In a new study, scientists at the University of Cincinnati used light to fight superbugs. But instead of traditional ultraviolet, the researchers used radiation with a longer wavelength to activate nanoparticles called photosensitizers. The latter react to light, producing a toxic form of oxygen.
"Instead of resorting to antibiotics that no longer work against certain bacteria, for example, methicillin-resistant staphylococcus, we use photosensitizers, mainly dye molecules that "wake up" when illuminated," says Peng Zhang, lead author of the study.
Then, the scientist continues, photosensitizers convert oxygen into active forms that are deadly for bacteria.
The principle described above is not new. It was developed a few years ago, but it has some serious drawbacks. Firstly, nanoparticles tend to spread, which makes it difficult to coordinate their attacks. Also, such particles are hydrophobic, which makes them difficult to use in a liquid. Meanwhile, microorganisms, as a rule, live in a humid environment or even in water and reservoirs.
To cope with this problem, scientists have developed hybrid particles combining photosensitizers with noble metal nanoparticles coated with amphiphilic polymers. According to the authors of the work, metals hold photosensitizers together, allowing them to strike at a more localized area. In addition, the metal helps to produce more reactive (and therefore aggressive) forms of oxygen.
When testing the new technique, the researchers found that the new particles were able to destroy various bacteria more effectively compared to preparations that do not contain metals. And during the testing of the technique on laboratory samples of human skin cells, experts found that the cells were not damaged. In other words, there are prerequisites for successful testing of the technique on humans.
Bacteria in a medium with nanoparticles before and after illumination – VM.
The authors of the development have already received a patent for a spray or gel containing nanoparticles. It could be applied to medical surfaces and equipment, after sterilizing them with blue or red light.
The study was presented at the 256th National Meeting of the American Chemical Community (Weaponizing oxygen to kill infections and disease).
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