Gold Nanoparticles Against Bacteria

Chemists from Tomsk Polytechnic University (TPU) are synthesizing gold spiky star-shaped nanoparticles and covering them with organic compounds. Tests proved the nanoparticles have an interesting property – under IR light exposure they exhibit antibacterial activity. Even in theory bacteria can’t be resistant to such particles, so they can be used for design of new materials applied in hospitals and in surgery rooms in particular, where new antibiotic-resistant bacteria are always appear. The results of this research have been recently published in the Chemistry Open.

Figure 1. Synthesis of modified gold multibranched nanoparticles (mod-AuMs-R; R=−COOH, −NH2, −NO2).

The research is carried out by the team of TPU Department of Organic Substances and Polymers together with colleagues from the University of Chemistry and Technology, Prague (UCT Prague). Dedicated reagents helped TPU scientists to modify gold nanoparticles through covalent grafting of organic compounds by using diazonium chemistry.

“We have modified Au nanoparticles surface so that through better interaction with bacterial membranes they demonstrate antibacterial properties.

Organic compounds on a particle surface provides better binding to bacterial membrane. Then, IR light triggers plasmon resonance and in fact nanoparticles start burning the cell membrane thus destroying the bacteria”,

says Associate Professor of the Department of Organic Substances and Polymers Pavel Postnikov.

According to the scientist, novel medical materials are a promising application of the star-shaped nanoparticles. For instance, such nanoparticles can be part of polymer materials applied in medical furniture and other products for surgery rooms and hospitals. Without light exposure, the material will be inert to or will have low antibacterial activity.

Photo: Associate Professor Pavel Postnikov

“Antibiotics are bacteria’s products as well. Therefore, bacteria can produce enzymes that destroy antibiotics. Antibiotic-resistant bacteria mainly appear in hospital conditions, which is an ideal place for their reproduction and natural selection. Nanoparticles of gold or other noble metals are absolutely foreign to bacteria.

Bacteria do not have any protective mechanism against nanoparticles. Nanoparticle can be compared to sledgehammer for bacteria, there is no protection against it”,

clarifies the chemist.

“The technology based on star-shaped nanoparticles is currently not applicable to fight bacteria inside a human body. However, in the future it can be used for treatment of skin diseases. It is a promising technology for new materials. Through varying shape, size of nanoparticles and metals, as well as wavelength of IR light you can obtain various materials with different functionality”, adds Pavel Postnikov.