World's thinnest material may prevent implant infection

At just one atom thick, graphene is the thinnest material known to man. Due to its high conductibility, graphene could be used in various electronic devices such as phone screens and chargers. New research adds to the list of uses for the material, as a thin layer of graphene is found to have an antibacterial effect.

Graphene was found in 2002, when an expert in microscopically thin materials decided to experiment with very thin layers of carbon.

The resulting "supermaterial" is now known as one of the world's strongest materials — in fact, it is 200 times stronger than steel — as well as the thinnest.

Made either as flakes or films, graphene is more electrically conductive than copper.

Previously, researchers have experimented with placing the graphene flakes vertically in an effort to expand its applications.

While structuring graphene as vertical "spikes" is not in itself innovative, scientists at the Chalmers University of Technology in Gothenburg, Sweden, are the first to demonstrate that placing the flakes vertically kills off bacteria and prevents infections in a surgical implant.

The findings — which have now been published in the journal Advanced Materials Interfaces — are particularly significant given that previous research yielded conflicting results, with some tests showing that it destroys bacteria and others leaving the bacteria unharmed.

"We discovered that the key parameter is to orient the graphene vertically," says co-corresponding study author Ivan Mijakovic, a professor in the Department of Biology and Biological Engineering at the Chalmers University of Technology. "If it is horizontal, the bacteria are not harmed," he explains.

How graphene can benefit implants

According to the Food and Drug Administration (FDA), medical implants are "devices or tissues that are placed inside or on the surface of the body." Some of these implants might replace body parts, such as hip or knee prosthetics, or they can simply support the good functioning of other organs.

The FDA caution that infections often accompany implants — especially immediately after surgery. Although usually such infections can be treated with appropriate medications, in some cases, the implant has to be removed altogether.

However, the new research shows that placing graphene flakes vertically on the surface of the implant forms a "spiky" protective shield that slices up the bacteria and prevents them from attaching.

Importantly, this protective layer does not harm human cells; human cells are 25 times larger than bacteria. The video below explains in further detail how graphene spikes work.

"Graphene has high potential for health applications," says co-corresponding study author Jie Sun, an associate professor in the Department of Micro Technology and Nanoscience at the Chalmers University of Technology.

Minimizing the risk of implant rejection, rendering antibiotics unnecessary, and protecting against infection are only some of these applications.

However, he cautions, "more research is needed before we can claim [graphene] is entirely safe. Among other things, we know that graphene does not degrade easily."

"We want to prevent bacteria from creating an infection. Otherwise, you may need antibiotics, which could disrupt the balance of normal bacteria and also enhance the risk of antimicrobial resistance by pathogens."

First study author Santosh Pandit, Department of Biology and Biological Engineering, Chalmers University of Technology