Researchers from the European Graphene Flagship Research Project recently explained how the graphene oxide suspension suspended in water undergoes biodegradation under the catalysis of a human enzyme, and the degree of this degradation is similar to that of the suspension. The stability of the colloid has a lot to do with it. This research has great guiding significance for the future application of graphene-based materials in biomedicine.

　　Like all new materials that are expected to be industrialized, the health and safety issues that graphene-based materials may cause have aroused great interest from a large number of experts and the public. The development and commercial application of graphene-based materials is still in its infancy, and the environmental problems, health and safety risks it brings are still under study. The researchers are mainly researchers related to the European Graphene Flagship Program. This flagship project is a large international consortium with academic and industrial partnerships, partially funded by the European Commission. Its purpose is mainly to focus on and solve the large-scale scientific and technological challenges that Europe needs to solve through long-term, multidisciplinary research.

　　The potential health and safety impact of two-dimensional materials including graphene materials is a focus worthy of in-depth study. When it comes to the commercial application of graphene-based materials, its persistence and long-term accumulation in the environment have become key issues. Therefore, after use, how to safely handle graphene-based materials and other engineering materials has become a key issue. A very interesting question. Specifically in terms of graphene, this two-dimensional oxidized form of carbon allotrope has huge application potential in some related fields such as drug release, bionics, tissue engineering, and biosensing, and all of this is attributable to Because of its high dispersibility and biocompatibility in water.

　　Graphene oxide material has a highly effective role in biomedical technology, but its toxicological effects must also be systematically studied and evaluated. Many related experimental studies have reported that graphene oxide materials can damage living cells and weaken the human immune response under certain circumstances. But when you consider it all together, you will find that the dates for these experiments are uncertain, and even contradictory in some cases.

　　Graphene and many of its compounds are biocompatible, but there are few research reports on its degradability. For this reason, a research team led by Alberto Bianco, an expert from the French National Research Council and one of the researchers of the flagship project, studied in detail the degradation of graphene oxide materials under the action of biological enzymes. The research results were published in the journal "Small". The researchers of the project stated that the myeloperoxidase extracted from human white blood cells and a small amount of low-concentration hydrogen peroxide can be used to remove highly dispersed graphene oxide samples. Completely metabolized and degraded.

　　The first author of this article published in the journal "Small" is RajendraKurapati, a postdoctoral student from the Bianco research group. Kurapati and colleagues mainly focused their research on the degradation ability of myeloperoxidase to degrade three different graphene oxide samples, which are mainly classified according to the degree of dispersion in water. It is worth noting that we are talking about dispersion and not the concentration of the material. Studies have found that under the action of myeloperoxidase, the more highly aggregated graphene oxide suspension is more difficult to degrade, and the more stable colloids can be completely decomposed under the action of enzymes. In terms of chemistry, the dispersibility of graphene oxide depends on the oxygen-containing groups on the surface of the graphene material, which in turn affects the biodegradability of the material.webcam factory

　　After introducing their experimental results in detail, the researchers began to discuss the degradation mechanism of graphene oxide. The discussion first summarized the infection process of myeloperoxidase against bacteria and other invasive materials that can cause inflammation of biological tissues. During inflammation, neutrophils, a subtype of white blood cells, gather in the infected area and secrete myeloperoxidase, which catalyzes the chemical reaction between chloride ions and hydrogen peroxide to produce strong oxidants , Such as hypochlorous acid. These oxidants have antibacterial properties and can degrade polyester grafts, extracellular sugars and oxidized carbon nanotubes. The authors of the study believe that the high redox potential of these oxidants produced during the chemical reaction catalyzed by myeloperoxidase will degrade the graphene oxide material in suspension in the same way. The most likely place where the material decomposes is mainly concentrated in the place where carbon atoms and oxygen atoms combine in the graphene lattice. In addition, the surface charge also has an effect on this process, as in the case of oxidized carbon nanotubes. Because it shows that the charge will make the graphene oxide and the biological enzyme can bind stronger, and then start to initiate the degradation reaction.

　　"Our experimental studies have proved that graphene oxide is completely degraded under the action of myeloperoxidase. At the same time, the results of the experiment also show that if humans or other organisms accidentally inhale graphene oxide, it may cause health risks. It can also be controlled". Bianco said: "On the other hand, in the biomedical field, if graphene-based materials are used as clinical biomedical materials, their biodegradability will also be considered. Our research provides a safe treatment of graphene-based materials and is A new method that is environmentally sound. Similarly, this has great guiding significance for the further development of graphene-based materials as a release carrier of biologically active molecules or medical drugs."

　　The specific degradation mechanism of graphene oxide is a subject that still needs further research and exploration, but the latest research results are also obvious. Graphene oxide is catalyzed by myeloperoxidase under the premise of the presence of hydrogen peroxide. Degradation. Moreover, the degree of degradation depends on the degree of colloidal stability of the suspension, which also shows that the hydrophilic nature of graphene oxide is a major factor in its ability to be degraded by myeloperoxidase. Therefore, when applying engineered graphene oxide materials to biomedical applications, the stability of the colloid should be considered.