Findings of a new research at the Chalmers University of Technology, Sweden, have shown that a layer of vertical graphene flakes forms a protective surface that makes it impossible for bacteria to attach. Instead, bacteria are sliced apart by the sharp graphene flakes and killed.
“Coating implants with a layer of graphene flakes can therefore help protect the patient against infection, eliminate the need for antibiotic treatment, and reduce the risk of implant rejection. The osseointegration – the process by which the bone structure grow to attach the implant – is not disturbed. In fact, the graphene has been shown to benefit the bone cells," the university said.
Chalmers University is deemed a leader in the area of graphene research, but the biological applications did not begin to materialise until a few years ago. The researchers saw conflicting results in earlier studies. Some showed that graphene damaged the bacteria, others that they were not affected.
“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.
Findings have also found that the sharp flakes do not damage human cells. “The reason is simple: one bacterium is one micrometre – one thousandth of a millimetre – in diameter, while a human cell is 25 micrometres. So, what constitutes a deadly knife attack for a bacterium, is therefore only a tiny scratch for a human cell,” read the statement, noting that good bacteria are also killed by the graphene. "But that’s not a problem, as the effect is localised and the balance of microflora in the body remains undisturbed."
Vertical graphene flakes form a protective surface that makes it impossible for bacteria to attach. Instead, bacteria are sliced apart by the sharp graphene flakes and killed. Human cells volume is typically 15,000 times larger. So, what constitutes a deadly knife attack for a bacterium, is therefore only a tiny scratch for a human cell (2)
Jie Sun, associate professor at the Department of Micro Technology and Nanoscience, commented: "Graphene has high potential for health applications. But more research is needed before we can claim it is entirely safe. Among other things, we know that graphene does not degrade easily.”
Vertical flakes of graphene have existed for a few years, however the Chalmers research team is the first to use the vertical graphene in this way. The next step for the research team will be to test the graphene flakes further, by coating implant surfaces and studying the effect on animal cells.
Chalmers cooperated in this research with Wellspect Healthcare, a manufacturer of catheters and other medical instruments. Wellspect will now continue with a second study.
The projects are a part of the national strategic innovation programme SIO Grafen, supported by the Swedish government agencies Vinnova (Sweden’s innovation agency), the Swedish Energy Agency and the Swedish Research Council Formas. The research results are published in Advanced Materials Interfaces: "Vertically Aligned Graphene Coating is Bactericidal and Prevents the Formation of Bacterial Biofilms"
Photo credit
- Photo 1: Johan Bodell/Chalmers University of Technology
- Photo 2: Yen Strandqvist/Chalmers University of Technology
