Graphene is not inherently toxic.
Previous studies claiming graphene is toxic were likely skewed because the material studied wasn’t really graphene or was created using toxic chemicals or harsh production methods
That’s the finding of a newly-released study from the National University of Singapore’s Centre for Advanced 2D Materials. The peer reviewed study reports that graphene toxicity is caused by materials misrepresented as graphene or impurities introduced during graphene processing.
This is good news for researchers seeking to use the fantastic properties of pristine graphene for next generation applications in medicine, medical devices and water filtration/purification.
“The toxicity of graphene, besides its dose, is not due to graphene itself but to the impurities that are a sub-product of graphene’s industrial processing,” writes Antonio H. Castro Neto, Director of the NUS Centre for Advanced 2D Materials and Institute for Functional Intelligent Materials.
“This important study highlights the link between high quality graphene and its many beneficial applications for the human body,” said Brad Larschan, CEO of graphene flake manufacturing company Avadain, Inc. “This study suggests that pristine graphene flakes manufactured without toxic chemicals or harsh processing may be good candidates for a wide range of uses, from purifying drinking water to advanced cancer treatments,” he added.
The study notes that “most of the graphene products available in the market are poorly characterized ‘black powders’.” Contamination can occur at different stages of production of materials, which the researchers refer to as “nominal graphene materials” (NGMs). The study observed that some production methods involve the use of chemicals that are not biocompatible and can cause adverse health effects. Further, harsh processing, the presence of intermetallic impurities and certain amounts of permanent structural defects in the hexagonal carbon framework can also impact NGM’s toxicity.
The NUS researchers examined 36 commercially available products marketed as “graphene” and found a surprisingly large variability in cytotoxicity, from harmless to highly toxic. The study noted that NGM products were investigated as received from suppliers, without any additional processing or modifications that could skew toxicity results.
The researchers concluded that over 35% of the samples contained highly defective graphene and all of the remaining samples contained organic and/or inorganic impurities.
Beyond cytotoxicity, the study noted that “the interactions between cells and graphene family materials vary in response to the material’s shapes, sizes, chemistries, and modes of use (particle suspension vs. substrates) inducing and modulating several cell responses, including the cell stability, survival, and toxicity.”