Graphene Combines with Drugs to Kill Bacteria

  • Bacterial infections associated with medical implants have brought a huge burden to medical care, and also brought huge pain to patients all over the world. Now, researchers at Chalmers University of Technology in Sweden have developed a new method to prevent this infection by covering graphene-based materials with germicidal molecules.


    "Through our research, we successfully combined water-insoluble antibacterial molecules with graphene, and released the molecules from the material in a controlled and continuous manner," SantoshPandit said, a researcher in the Department of Biological and Bioengineering at Charmers University, and he was also the first author of the study, which was recently published in the Scientific Report.


    "This is the basic requirement for this method to work. Our method of combining active molecules with graphene is also very simple and can be easily integrated into industrial processes."


    Certain bacteria can form an impenetrable surface or "biofilm" on surgical implants (such as dental and other orthopedic implants), which is a major problem in global healthcare. Biofilms are more resistant than other bacteria, so infections are often difficult to treat and cause great pain to the patient. In the worst case, the implant needs to be removed or replaced. In addition to the impact on patients, this will also bring huge costs to healthcare providers.


    There are a variety of water-insoluble or hydrophobic drugs and molecules that can be used for its antibacterial properties. But in order for them to be used in the body, they must be attached to a material, and the manufacture of this material can be difficult and labor-intensive.


    "Graphene offers great potential in interacting with hydrophobic molecules or drugs, and when we created our new materials, we took advantage of these properties. The process of combining antimicrobial molecules is carried out with the help of ultrasound," Santosh Pandit said.


    In this study, the graphene material was covered with sorellic acid, which was extracted from lichens, such as glycan lichens. Previous studies have shown that Tricholoma matsutake acid has good bactericidal properties. It works by preventing bacteria from forming nucleic acids, especially by inhibiting RNA synthesis, thereby preventing protein production in cells.


    Usnic acid tested its resistance to the pathogenic bacteria Staphylococcus aureus and Staphylococcus epidermidis, which are common causes of biofilm formation in medical implants. The researchers' new material shows many promising properties. In addition to successfully integrating the usnic acid into the surface of the graphene material, they also observed that the usnic acid molecules were released in a controlled and continuous manner, thereby preventing the formation of surface biofilms.


    "More importantly, our results show that the method of combining hydrophobic molecules with graphene is very simple. It lays the foundation for more effective antibacterial protection of biomedical products. We are now planning to conduct trials in which we will explore the combination of other hydrophobic molecules and drugs with greater potential to treat or prevent various clinical infections," Santosh Pandit said.


    The sustained release of usnic acid from the graphene coating ensures long-term antibiotic film protection


    The research project was led by Professor Ivan Mijakovic from the Department of Biology and Biotechnology at Chalmers University of Technology in Sweden. It is funded by Formas and the Swedish Research Council.