Graphene Spike Mat and Fridge Magnet

With its powerful antibacterial properties, graphene has the potential to be a breakthrough in the fight against antibiotic-resistant bacteria. Until now, there has been no effective way to control these properties – and therefore no way to harness graphene’s potential in healthcare. Now, researchers at Chalmers University of Technology in Sweden have solved the problem by using the same technology found in an ordinary fridge magnet. The result is an ultra-thin, acupuncture-like surface that could act as a coating on catheters and implants – killing 99.9 percent of all bacteria on the surface.

Healthcare-associated infections are a common problem worldwide, causing great suffering, high healthcare costs and an increased risk of increased antibiotic resistance. Most infections occur in association with the use of various medical technology products such as catheters, hip replacements, knee replacements and dental implants, where bacteria can enter the body through a foreign surface. At Chalmers University of Technology, scientists have been investigating how graphene, an atomically thin two-dimensional graphite material, could contribute to combating antibiotic resistance and infections in healthcare. The research team had previously been able to show how vertically aligned graphene sheets prevent bacteria from attaching to a substrate. Instead, the bacteria are cut into pieces on the razor-sharp sheets and die.

“We are developing a graphene-based, ultra-thin, antibacterial material that can be used on any surface, including biomedical devices, surgical surfaces and implants, to exclude bacteria. “Because graphene prevents bacteria from physically adhering to the surface, it has the added advantage that you don’t risk the development of antibiotic resistance, unlike other chemical alternatives, such as antibiotics,” says Ivan Mijakovic, professor of systems biology at Chalmers University of Technology and one of the authors of the recently published study.

Kills 99.99% of bacteria on surfaces

But scientists face a challenge. Although its antibacterial properties can be demonstrated in the lab, scientists have not yet been able to control the orientation of graphene flakes – and consequently have not been able to use the material on surfaces used in medical devices used in healthcare. Until now, graphene’s antibacterial properties could only be controlled in one specific direction: the flow direction of the manufacturing process. But now, scientists at Chalmers have achieved a promising breakthrough with practical applications in healthcare – and beyond.

“We have managed to find a way to control the effects of graphene in practically several different directions and with a very high level of orientation uniformity. This new orientation method makes it possible to integrate graphene nanoplatelets into medical plastic surfaces and obtain an antibacterial surface that kills 99.9% of the bacteria that try to attach. This opens the way to much greater flexibility when you want to produce bacteria-killing medical devices using graphene,” says Roland Kádár, Professor of Rheology at Chalmers University of Technology.

Unprecedented efficiency by controlling magnetic fields

By arranging the Earth magnets in a circle and obtaining a straight direction of the magnetic field inside the system, the researchers were able to obtain a uniform orientation of graphene and obtain a very strong bactericidal effect on surfaces of any shape.

Method published in Advanced functional materials, is called a “Halbach array” and means that the magnetic field inside the magnet array is strengthened and uniform, while it is weakened on the other side, allowing for a strong unidirectional orientation of the graphene. The technology is similar to that found in a refrigerator magnet.

“This is the first time that the Halbach array method has been used to orient graphene in a polymer nanocomposite. Now that we have seen the results, we obviously want to introduce these graphene platelets into the healthcare sector so that we can reduce healthcare-associated infections, reduce patient suffering and counteract antibiotic resistance,” says Viney Ghai, a researcher in rheology and soft matter processing at Chalmers University of Technology.

The new orientation technology shows significant potential in other areas, for example in batteries, supercapacitors, sensors and durable, waterproof packaging materials.

“Given the broad impact of this method in these areas, it opens up new horizons in materials tailoring, providing a powerful tool to efficiently design and tailor nanostructures that biomimic complex architectures found in natural systems,” says Roland Kádár.

Caption under the illustration: Illustration showing how razor-sharp graphene flakes align on a surface and can kill bacteria without harming healthy human cells. Bactericidal graphene surfaces developed at Chalmers University of Technology could soon find their way into medical devices thanks to a completely new method that uses fridge magnet technology to control graphene’s germicidal effects.

Illustration source: Yen Sandqvist

Caption under graphic 2: Summary illustration of the new Halbach magnetic field orientation scheme, where the red/blue arrows indicate the magnetization direction of the individual magnets, and a numerical simulation showing the magnetic field lines inside the magnet system where the magnetic field strength reaches 1 Tesla.

Image source: Roland Kadar; numerical simulation using Comsol Multiphysics software

More about the study:

Read the study: Achieving arbitrary, uniform alignment of nanostructures in long-range magnetic fields.

The study was conducted within the competence centre 2D-TECH, hosted by Chalmers University of Technology. The centre is funded by Vinnova, Chalmers and 19 industrial partners and is the Swedish research and innovation centre for 2D materials technology for industrial applications.

For more information, please contact:

Roland Kádár, Professor of Rheology at the Department of Industrial Science and Materials Science at Chalmers University of Technology
[email protected]
+46-31-772 12 56

Viney Ghai, a researcher in rheology and soft matter processing at the Department of Industrial Science and Materials Science at Chalmers University of Technology
[email protected]

Ivan Mijakovic, Professor of Systems Biology at the Department of Life Sciences at Chalmers University of Technology
[email protected]

Roland Kádár speaks English and Viney Ghai speaks English, Hindi and Punjabi. Both are available for live and pre-recorded interviews. Chalmers has podcast radio studios and filming facilities available for TV, radio or podcast enquiries.

More about the method:

In laboratory experiments, the researchers exposed different bacterial cultures to graphene surfaces whose magnetic fields had been manipulated according to the new method. To calculate the effectiveness of the method, they measured bacterial survival using CFU (colony forming unit), a tool that measures the number of microorganisms in a bacterial colony. Using scanning electron microscopy (SEM), the researchers were also able to scan the bacterial colonies to visualize and confirm with images the physical disruption of graphene on the bacterial cells.

More support materials – video:

Watch a video showing how a thin layer of graphene flakes becomes a deadly weapon, killing bacteria and preventing infections during procedures such as implants: https://youtu.be/qkTmNKiGTlM