Fighting bacteria with nanoparticles

Multi-resistant pathogens are a serious and increasing problem in today's medicine. Researchers at Empa and ETH Zurich have now developed a completely new method that allows multi-resistant pathogens to be killed in a targeted manner.

In the "mankind against bacteria" arms race, bacteria are currently ahead of us. Our former miracle weapons, antibiotics, are failing more and more frequently when germs use tricky manoeuvres to protect themselves from the effects of these drugs. Some species even retreat into the inside of human cells, where they remain "invisible" to the immune system. These particularly dreaded pathogens include multi-resistant staphylococci (MRSA), which can cause life-threatening diseases such as sepsis or pneumonia.

The team at Empa and ETH Zurich led by Inge Hermann and Tino Matter have developed nanoparticles that use a completely different mode of action from conventional antibiotics. While antibiotics have difficulty in penetrating human cells, these nanoparticles, due to their small size and structure, can penetrate the membrane of affected cells. Once there, they can fight the bacteria.

Metal oxides destroy bacteria
The particles containing cerium dissolve bacteria when they come into contact with them. While other metals also have antimicrobial effects, they are frequently harmful to body cells at the same time, as is the case for silver. Cerium oxide, by contrast, is very well tolerated. The researchers currently assume that the nanoparticles affect the cell membrane of the bacteria and destroy it. Since the membrane of human cells is structurally different, body cells are not affected by this process.

Fewer resistances
The researchers think that resistance is less likely to develop against a mechanism of this kind. “What’s more, the cerium oxide particles regenerate over time, so that the effect of the nanoparticles on the bacteria can start all over again”, says Empa researcher Tino Matter. “In this way, the cerium oxide particles could have a lasting effect”. Tino Matter and his team are working on bringing the new technology to market. His startup, anavo medical, has already celebrated a number of successes – including the award for the best Swiss Nanotechnology Startup in 2021. The young team is currently looking for investors.

Last modification 14.11.2021

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Fatal contact: researchers at Empa and ETH Zürich have developed nanoparticles (red) that can kill resistant bacteria (yellow).
Figure: post-coloured electron micrograph, Empa.