Antibacterial nanoparticles
Russian scientists have created nanoparticles that selectively kill bacteria
Biophysicists from Russia and Ukraine has developed unusual nanoparticles that destroy pathogenic microbes when irradiated with light, but at the same time almost do not damage animal and fungal cells, according to an article published in the journal JPPB: Biology (Popov et al., Photo-induced toxicity of tungsten oxide photochromic nanoparticles).
"The data we have obtained not only suggests that tungsten oxide nanoparticles can be used in medicine, but also indicate that they must be handled very carefully when used in everyday life and medical practice," write Anton Popov, a biophysicist from the Institute of Theoretical and Experimental Biophysics of the Russian Academy of Sciences in Pushchino, and his colleagues.
In recent years, foreign and Russian scientists are increasingly trying to use various nanoparticles to fight cancer, infectious diseases or to treat non-communicable diseases.
Sometimes nanoparticles themselves serve as a means to remove tumors or as "killers" of microbes and viruses, acting as a kind of "target" to which either immune cells or laser radiation are induced, heating particles and burning cells.
In other cases, nanoparticles are only a means of delivering toxic molecules to a tumor or a focus of infection, which limits their action and reduces the dose necessary for the complete destruction of pathogens. As a rule, such nanoparticles consist of organic compounds that are "invisible" to immunity.
Popov and his colleagues have been studying the properties of nanoparticles made of oxides of various metals with unusual properties for several years. For example, two years ago they managed to find out that nanoparticles of cerium, a rare earth metal, protect human and animal cells from radiation, and also stimulate the growth of stem cells.
Recently, scientists from ITEB RAS and their colleagues from other institutes of the Russian Academy of Sciences and the Academy of Sciences of Ukraine began to study the properties of nanoparticles made of tungsten oxide – a substance with strong bactericidal properties. These properties are due to the fact that when interacting with light, tungsten oxide heats up, and also produces a large number of aggressive molecules if it is in water or in another liquid medium.
Biophysicists have noticed for a long time that reducing the particle size of this oxide significantly enhances its "killer" qualities. This gave them the idea to create nanoparticles from tungsten oxide and test how they would interact with various cultures of pathogenic microbes, fungi and animal cells.
These experiments revealed the unusual selectivity of the action of such nanoparticles, useful from the point of view of practice. As it turned out, they killed microbes even at very low concentrations, had a much worse effect on the connective tissue cells of mice, and had almost no effect on the vital activity of fungal cultures.
Drawings from the article in JPPB: Biology – VM.
"Apparently, this is due to the morphological features of their cell membranes and different metabolism," notes Popov, whose words are reported by the press service of the ITEB RAS.
What is even more interesting, such nanoparticles penetrate much more easily into cancer cells than into healthy tissues of the human body, which makes it possible to use small doses of tungsten oxide, harmless to the body, to "burn out" tumors and simultaneously obtain their photos.
On the other hand, large amounts of these nanoparticles can still harm humans. Therefore, as scientists emphasize, they need to be used very carefully both in medicine and in everyday life, for example, when disinfecting rooms or creating bactericidal films for "smart" glasses and other electronic gadgets.
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