Antimicrobial resistance (AMR) is one of the most serious health threats of our time.
It means that within a few decades we might no longer be able to treat bacterial infections with antibiotics. It is therefore crucial that new drugs are developed that can provide an alternative to current antibiotics.
This has been the main goal of a Nordic research group Graphene-based drug delivery systems for treating MRSA infections (GraMI) | NordForsk, which has now come up with a possible strategy to fight multidrug resistant Staphylococcus aureus, also known as MRSA. These are bacteria normally found on human skin and mucous membranes that can cause infections.
Ivan Mijakovic is a professor at Chalmers University in Sweden and is leading the project.
"There are not as many new antibiotics being produced worldwide anymore and bacteria are becoming more and more resistant. This is a huge problem. In our project, we wanted to develop a new weapon against bacteria, and we can now present a possible alternative to the antibiotics on the market," he says.
The project is interdisciplinary and has three partners - Chalmers University, SINTEF in Norway and the Technical University of Denmark. They have each developed a component that together form what could become a new treatment against antibiotic resistance.
Water in the human body
The human body is 75 per cent water. When we take medicine in the form of pills, the medicine is dissolved by the water in our body.
Researchers from the project found a molecule that was very effective against bacteria, which is the whole purpose of an antibiotic. Compared to the classic antibiotics on the market that you can buy at the pharmacy, this is far more potent. But there is a fundamental problem with the chemistry of the molecule.
"The problem with this antibiotic is that you can't put it in a pill and give it to people because it can't dissolve in water and it won't be effective against bacteria. Despite its great potential, the researcher could not move forward. So that's one of our three components. A very strong but useless antibiotic because of the hydrophobic property," says Ivan Mijakovic.
Egyptian mummies
We know from Egyptian mummies that ancient Egyptian pharaohs used gold or silver tools to treat diseases. Some of the preserved mummies have dental implants made of gold or silver. They are known to kill bacteria.
Researchers from the Technical University of Denmark have developed a technology to make tiny nanoparticles of gold and silver. They are antimicrobial and can kill bacteria. The fact that they are so small, the nano aspect, also means that they can be dissolved in water. They can even be injected into the bloodstream as a treatment.
"They are not yet approved for human use, but there have been many trials in laboratory animals where the tiny nanoparticles have been injected and have been able to fight infections. But they also have certain limitations. Just like the antibiotic from the first component, these nanoparticles also have good and bad sides," says Ivan Mijakovic.
The black trace of a pencil
If you write on a piece of paper with a classic pencil, the pencil leaves a black trace.
This is because the carbon in the pencil is made of thin layers of carbon atoms. A single layer of carbon atoms is called graphene. If you have many thin layers that are put together, you have a pencil. When you write with a pencil, there's friction between the pencil and the paper and the pencil loses some of these graphene layers, which fall off and stay on the paper.
"We found that if you put the graphene layers next to each other so that they form a dense forest with the sharp edge facing up, bacteria have a problem because the graphene layers are like molecular blades. They are very sharp and can cut into bacteria," he says, adding:
"Bacteria can't protect themselves from the sharp knife because it's not chemical killing. It's a mechanical, physical killing principle, and bacteria have no defence against that. We have also shown that if you expose the few surviving bacteria to these sharp knives again, they do not become more resistant over time. The knives are simply an insurmountable challenge for them."
Antibacterial 'weapon'
The graphene layers are the third and final element of what could become a new antibacterial treatment.
"Together, these three components form an antibacterial 'weapon' that is very effective against bacteria. So, we have the first hydrophobic antibiotic, the metallic nanoparticles, silver or gold, which are also toxic to bacteria, and these graphene knives, which do mechanical damage to bacteria. With this three-pronged approach, we are trying to attack bacteria from different sides at the same time" says Ivan Mijakovic.
The new antibacterial “weapon” has not yet been approved for use. The project's researchers hope to have clinical trials in the future, so that it may eventually be approved and used for treatment.
