The ‘wonder material’ graphene, a material first isolated by scientists in 2004, has been gaining a lot of attention lately with a wide range of potential applications in electronics, phone screens, clothing, paints, and water purification.
Moreover, researchers around the world are actively exploring graphene’s potential use in targeted therapeutics against cancer and other health conditions, as well as implantable devices and sensors. The oxidized form of graphene, graphene oxide (GO), has shown promise in the biomedical setting due to its chemical and mechanical stability, hydrophilic properties, high surface area, and biocompatibility. However, before any medical application, the safety profile and limitations of GO on human exposure need to be determined.
Although graphene oxide nanomaterials are associated with potential safety concerns for human health, the study conducted by researchers from the Universities of Edinburgh and Manchester suggests that carefully controlled inhalation of this material may be safe.
The first-in-human study has found that inhaling this specific type of graphene, the world’s thinnest, super strong and super flexible material, has no short-term adverse effects on lung or cardiovascular function.
“Nanomaterials such as graphene hold such great promise, but we must ensure they are manufactured in a way that is safe before they can be used more widely in our lives,” said Mark Miller, one of the study’s corresponding authors. “Being able to explore the safety of this unique material in human volunteers is a huge step forward in our understanding of how graphene could affect the body. With careful design, we can safely make the most of nanotechnology.”
In a recent study, researchers synthesized highly purified metal- and endotoxin-free GO nanosheets in two dimensions – small GO (s-GO) and ultrasmall GO (us-GO) – and aerosolized them for inhalation via a face mask.
The study involved fourteen healthy participants who inhaled either a single dose of GO or filtered air for two hours while cycling in a purpose-designed mobile exposure chamber brought to Edinburgh from the National Public Health Institute in the Netherlands.
The results showed that the inhalation of GO was neither associated with any acute adverse effects on the participants’ lung or cardiovascular function nor systemic inflammation. However, a mild increase in thrombogenicity was observed in an ex vivo model of vascular injury, indicating the need for further studies to fully evaluate the actions of inhaled manufactured nanomaterials.
While the use of controlled exposures in human participants has many advantages, researchers acknowledge their study has several limitations. They pointed out that the number of participants was small and that they were only able to test a single dose of GO. The small sample size may have prevented them from detecting more subtle effects of GO inhalation or that higher concentrations or longer exposure durations could produce effects that were not apparent in the current study.
Nevertheless, the researchers believe that the study represents a significant step forward in assessing the risks associated with the use of GO in the biomedical field.
“This is the first-ever controlled study involving healthy people to demonstrate that very pure forms of graphene oxide – of a specific size distribution and surface character – can be further developed in a way that would minimize the risk to human health,” said Professor Kostas Kostarelos of the University of Manchester and the Catalan Institute of Nanoscience and Nanotechnology (ICN2) in Barcelona. “It has taken us more than ten years to develop the knowledge to carry out this research, from a materials and biological science point of view, but also from the clinical capacity to carry out such controlled studies safely by assembling some of the world’s leading experts in this field.”
Researchers say further work is needed to study the impact of graphene oxide material and whether higher doses or longer exposure to it could pose health risks.
Journal reference:
- Jack P. M. Andrews, Shruti S. Joshi, Evangelos Tzolos, et al. First-in-human controlled inhalation of thin graphene oxide nanosheets to study acute cardiorespiratory responses. Nature Nanotechnology, 2024; DOI: 10.1038/s41565-023-01572-3