Carbon nanoparticles stick to bacterial membranes and puncture them. On new type of antibiotic tools
The large ratio between the number of atoms on the surface of nanoparticles and their total number of atoms - gives these structures special chemical and physical properties. Prof. Raz Yelink, a multidisciplinary chemist and the vice president and dean for research and development at Ben Gurion University of the Negev, researches carbon nanoparticles and, among other things, produces antibacterial substances from them.
"I focus on carbon nanoparticles because they are easy to produce in the laboratory and are cheap and environmentally friendly," he says. "In addition, they have special physical and optical properties. For example, they stick to the membrane (membrane) of the bacterium, to its outer surface, pierce it using chemical residues present on them and thus kill it. Therefore, they can be used as a kind of new type of antibiotic, which is not toxic. In addition, when these substances come into contact with certain bacteria, they stick to them and mark them with a fluorescent, glowing light (biological sensing), and thus they can be seen under a microscope."
What is the question? How do carbon nanoparticles affect different bacteria?
In their laboratory, Prof. Yelink and his team heat simple and cheap hydrocarbon substances from nature (such as sugar, chickpea seeds and amino acids), thus producing carbon nanoparticles that manage to identify bacteria and stick to them ("That's the beauty, simply," notes Prof. Yelink). In their latest study, which won a grant from the National Science Foundation, the researchers heated amino acids that contain carbon and nitrogen for several hours to a temperature of 100-90 degrees, and thus succeeded in producing nanoparticles from them in large quantities. "When you heat the amino acids for many hours, they crystallize and stick together. This is how nanoparticles are created from them, the uniqueness of which is molecular groups of amino acids. These groups are found on the outer surface of the nanoparticles", explains Prof. Yelink.
Later, the researchers wanted to check how these nanoparticles affect a variety of bacteria, with different types of membranes. For this purpose, they were added in different concentrations to bacteria in Petri dishes containing a growth medium. According to Prof. Yelink, "We tested the nanoparticles on different types of bacteria and membranes. For example, bacteria that cause diseases such as pneumonia and intestinal diseases. We also examined the way in which the nanoparticles affect the biofilm - an opaque and impenetrable layer (a mixture of extracellular substances such as proteins and sugars), which bacteria build around them when they form large colonies, through which they manage to overcome the penetration of antibiotic substances."
Using microscopic methods, the researchers saw that nanoparticles in a relatively large concentration were able to stick to the membrane of gram-negative bacteria, especially the bacterium Pseudomonas aeruginosa (which is involved in serious diseases such as pneumonia and sepsis syndromes, and has elaborate resistance mechanisms to antibiotics), and to pierce it and thus kill the bacteria. When the nanoparticles were at a low concentration, they were able to stick to the membrane of bacteria - but not pierce it. At this concentration they were also able to label the bacteria with fluorescent light. In addition, they were able to break down biofilms of common bacteria.
We tested the nanoparticles on different types of bacteria and membranes. For example, bacteria that cause diseases such as pneumonia and intestinal diseases.
Today, researchers continue to examine these nanoparticles and the possibilities of basing additional microbiological applications on them. For example, they developed an "electronic nose" (sensor) that smells bacteria; It consists of nanoparticles with chemical residues that are attracted to molecules secreted by the bacteria, thus absorbing them from the air. This way you can know that the bacteria are in the environment. Such an "electronic nose" can detect, for example, bacteria in food, in hospitals, in air conditioning systems, in vehicles, and more.
Life itself:
Prof. Raz Yelink, 58 years old, lives in Modi'in and likes long distance running.
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