Gold Nanowalls
Chemists of Tomsk Polytechnic synthesize gold nanoparticles capable of destroying bacteria under the influence of light
Scientists of Tomsk Polytechnic University synthesize gold nanoparticles of a special star shape and cover them with organic compounds. The experiments have proved that these nanoparticles have an interesting property – they exhibit antibacterial activity under the influence of laser radiation. Even theoretically, bacteria will not be able to develop resistance to such particles, so they can be used to create new materials for hospitals and, in particular, operating rooms, where all new types of antibiotic-resistant bacteria are found. Data on this study were recently published in the journal Chemistry Open (Kalachyova et al., Synthesis, Characterization, and Antimicrobial Activity of Near-IR Photoactive Functionalized Gold Multibranched Nanoparticles).
Schematic diagram of obtaining surface-modified nanoparticles
The research is conducted by a team of scientists at the Department of Technology of Organic Substances and Polymer Materials of Tomsk Polytechnic University together with colleagues from the Chemical Technology University of Prague. Gold nanoparticles synthesized by polytechnics are called "stellate" due to their shape. With the help of specially created reagents, TPU scientists managed to apply organic compounds to their surface by covalent surface modification using aromatic diazonium salts.
"Stellate nanoparticles and methods of their synthesis have already been described. We also managed to modify their surface so that they interact better with cell membranes and demonstrate their antibacterial properties.
Organic compounds on the surface of the particles allow them to attach better to the membrane. Then the physics of the process comes into play: the laser excites the plasmon resonance, and the nanoparticles actually begin to burn through the cell membrane, destroying the bacterium," says Associate professor of the Department of Technology of Organic Substances and Polymer Materials Pavel Postnikov.
According to the scientist, a promising direction of using stellate nanoparticles is new medical materials. For example, particles can be part of polymer materials used to make operating tables, furniture and other items for operating rooms and hospitals. Without light exposure, the material will be inert or weakly exhibit antibacterial activity.
"Antibiotics are products of the same bacteria. Therefore, bacteria can produce enzymes that destroy the antibiotic. Antibiotic-resistant bacteria mainly appear in hospital settings, here is an ideal place for their reproduction and natural selection. And nanoparticles of gold or other precious metal are absolutely alien to the bacterium material.
Bacteria have no defense mechanisms against nanoparticles, and even in theory they cannot develop resistance. Nanoparticles can be compared to a sledgehammer for a bacterium, there is simply no protection against it," the scientist explains.
Now in hospitals, ultraviolet radiation from a quartz lamp is used to combat pathogens. But during the quartz movement, people should not be indoors. In turn, the wavelength of light radiation that activates the antibacterial activity of gold nanoparticles is safe for humans.
"The technology using stellate nanoparticles and a laser is not suitable for fighting bacteria inside the body at this stage. However, in the future it can be used for the treatment of skin diseases. In the field of new materials, this is a very interesting direction. By choosing the shape, size of nanoparticles, metals themselves, varying the wavelength of the laser, it is possible to obtain various materials with different functional activity," adds Pavel Postnikov.
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29.03.2017