Graphene method could prevent medical implant infections

Certain bacteria can form impenetrable biofilms on surgical implants such as dental and other orthopaedic implants. Biofilms are more resistant than other bacteria and infections can be difficult to treat, causing suffering for patients and in some cases necessitating costly replacements of implants.

Various hydrophobic drugs and molecules can be used for their antibacterial properties, but must be attached to a material to be used in the body which can be difficult to manufacture. 

Now, researchers at Chalmers University of Technology said they have  succeeded in binding water-insoluble antibacterial molecules to graphene and having the molecules release from the material in a ‘controlled, continuous’ manner. 

Santosh Pandit, first author of the study and researcher at Chalmers’ Department of Biology and Biological Engineering, said that this is an essential requirement for the method, describing the process as ‘very simple’ with potential for easy integration into industrial processes.

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“Graphene offers great potential here for interaction with hydrophobic molecules or drugs, and when we created our new material, we made use of these properties,” Pandit said in a statement. “The process of binding the antibacterial molecules takes place with the help of ultrasound.”

For the study, published in Scientific Reports, researchers said they covered the graphene material with usnic acid, which is extracted from lichens such as fruticose lichen. Previous research shows that usnic acid has good bactericidal properties that prevent bacteria from forming nucleic acids, inhibiting RNA synthesis and blocking protein production in the cell.

Usnic acid was tested for its resistance to the pathogenic bacteria Staphylococcus aureus and Staphylococcus epidermidis, two common culprits for biofilm formation on medical implants. The material displayed ‘promising properties’, the team said, successfully integrating the usnic acid into the surface of the graphene material and preventing formation of biofilms on the surface.

Pandit said that the method could pave the way for more effective antibacterial protection of future biomedical products, adding that the team is now planning trials to explore binding other hydrophobic molecules and drugs with greater potential to treat or prevent various clinical infections.