UPDATE: My original article on this subject is now online with Materials Today.
It was almost inevitable that the naysayers and scaremongers would start to express concerns about graphene, the new wonder material that won its developers a Nobel prize for their work with sticky tape and HB pencils. It’s sensible to look at graphene if there are risks and Ken Donaldson, a respiratory toxicologist at the University of Edinburgh, and his colleagues have been among the first to raise the warning flag on graphene, at least for nanoscopic platelets of the stuff. In case you didn’t know graphene is essentially a single, monolayer, of graphite, the carbon allotrope found in soot, charcoal and, yes, the “lead” in an HB pencil.
Donaldson’s work seems to suggest that flakes of graphene if they get into the lungs might cause health problems. However, I, and some of my contacts in the field of nanotechnology and safety are not so sure it will ever be a real health problem even for scientists working with graphene nano-flakes.
Andrew Maynard of 2020Science.org is Director of the Risk Science Center at the University of Michigan and had this to say of the Donaldson work:
“This is an interesting area of health impact speculation and research. Donaldson’s work certainly demonstrates the potential for graphene flakes to present a health risk if they are able to be inhaled and enter the lungs, or penetrate to the region surrounding the lungs,” Maynard says. He then went on to tell me that this is a big ‘if’. “Pharyngeal aspiration delivers particles – or platelets in this case – to the lungs within liquid droplets – the droplets determining where the material is deposited,” he added. “It allows early experimentation on what could occur if the material could enter the lungs under handling and use. But it doesn’t provide information in the plausibility of exposure occurring. And without knowing whether graphene flakes can become airborne and inhaled in a form that is dangerous during use, questions concerning health risks – while important – remain speculative.”
It is important to point out that any safety issues with regards to graphene will be very dependent on the shape and surface of the particles. Lab tests can make all kinds of claims but do not necessarily reflect how the flakes would behave when in contact with living tissue or whether there is actually a mechanism for problematic exposure at all. It might be that graphene would not be a problem at all, after all macrophages can usually cope with particles up to about 10 micrometres in diameter. Platelets of this size shouldn’t be a challenge and any larger would suggests that they wouldn’t be able to get into the lungs anyway.
Intriguingly, the Nobel-winning studies on graphene simply used pencil lead and sticky tape to produce the material, countless generations have been exposed to such materials for many years, could we have unwittingly been exposed to graphene flakes all this time?
Schinwald, A., Murphy, F., Jones, A., MacNee, W., & Donaldson, K. (2012). Graphene-Based Nanoplatelets: A New Risk to the Respiratory System as a Consequence of Their Unusual Aerodynamic Properties ACS Nano, 6 (1), 736-746 DOI: 10.1021/nn204229f