Graphene spikes can kill bacteria on implants

Robert Scammell 16 April 2018 (Last Updated April 16th, 2018 14:33)

Researchers have shown that a tiny layer of vertical graphene flakes can be applied to implants to prevent bacterial infection.

Graphene spikes can kill bacteria on implants
Graphene is the world’s thinnest material at only a single atomic layer thick, but is 200 times stronger than steel.

Researchers have shown that a tiny layer of vertical graphene flakes can be applied to implants to prevent bacterial infection.

The research team from Chalmers University of Technology, Sweden, claim that spiked-shaped graphene flakes can slice apart bacteria that attempt to attach to the surface of a coated implant. This protection could combat infection, eliminate the need for antibiotic treatment and reduce the risk of implant rejection.

“We want to prevent bacteria from creating an infection,” said Santosh Pandit, a post-doctorate researcher at Chalmer’s Department of Biology and Biological Engineering.

“Otherwise, you may need antibiotics, which could disrupt the balance of normal bacteria and also enhance the risk of antimicrobial resistance by pathogens.”

While some research previously showed graphene’s potential to fight bacteria, the results were inconclusive. The Chalmers team discovered that orientating the graphene layer vertically was crucial to fighting off bacteria, which travel around the body in fluids looking for a surface to cling to.

“We discovered that the key parameter is to orient the graphene vertically. If it is horizontal, the bacteria are not harmed,” said Ivan Mijakovic, professor at the Department of Biology and Biological Engineering.

Graphene, made from carbon atoms, is the world’s thinnest material at only a single atomic layer thick. With a bacterium measuring just one micrometre and a human cell 25 micrometres, the sharp flakes do not cause any notable damage to human cells.

While good bacteria are also killed by the graphene, the damage is localised and therefore the balance of microflora in the body remains undisturbed.

To produce vertical graphene forms, the team used a process known as plasma-enhanced chemical vapour deposition. An electric field is applied over the sample, which causes the gas to be ionised near the surface. With the plasma, the layer of carbon grows vertically from the surface, instead of horizontally as with traditional chemical vapour deposition techniques.

With its good conductivity and a strength measuring 200 times that of steel, graphene has potential applications across many sectors including medicine, electronics, energy and sensors. However, the researchers cautioned that more tests are needed before it can be used in the body.

“Graphene has high potential for health applications,” said Jie Sun, associate professor at the Department of Micro Technology and Nanoscience.

“But more research is needed before we can claim it is entirely safe. Among other things, we know that graphene does not degrade easily.”

Chalmers cooperated with medical instrument manufacturer Wellspect Healthcareers during the research and they plan to proceed with a second study that tests the graphene flakes further by coating implant surfaces and studying the effects on animal cells. Funding was provided by Vinnova, a Swedish government agency.

The findings were published in the scientific journal Advanced Materials Interfaces.