Graphene-related materials (GRMs) are often used to reinforce polymers. In small concentrations of up to 5% (weight), they can significantly enhance the strength, electrical conductivity and thermal transport of composites for a variety of applications. However, limited information is available concerning the hazard potential of GRM-containing products such as graphene-reinforced composites. In a new study, researchers conducted a comprehensive investigation of the potential biological effects of particles released through an abrasion process from a composite of polyamide 6 (PA6, also known as Nylon-6) with 2.5% reduced graphene oxide (rGO).
Graphene and its derivatives have been among the fastest growing areas of nanoscience and technology over the past decade.
This atomically thin, two-dimensional form of carbon has generated considerable excitement since its initial discovery.
Due to its outstanding physicochemical properties, namely, excellent stretchability (20% of its initial length), high intrinsic mechanical stiffness and strength, extraordinary electrical conductivity, large surface area, and superior thermal conductivity, it has raised high expectations on future applications.
Many of these properties are superior to those of other materials, but most importantly, the combination of all these characteristics is exceptional.
It is of no surprise that GRMs are currently being explored for a multitude of applications, such as in electronics, energy, photonics, composite, filtration, sensors, or biomedicine.
As a result of the increased demand, production of GRMs has increased from 14 tons in 2009 to nearly 1,200 tons per year within just a decade.
By 2025, the market value is projected to reach between US$180 million to US$2.1 billion per year, with about 30% of the annual growth rate for graphene reinforced composites.
In the new study, a research team funded by the EU’s Graphene Flagship project analyzed and compared the effects of the abraded particles consisting of either PA6-rGO, PA6 alone or pure rGO along the most likely exposure routes.
They used cell-based models representing human lungs, the gastrointestinal tract, the skin and the immune system as well as an in vivo mouse model for pulmonary exposure.
They found only limited acute responses after exposure to PA6-rGO in the different cell-based models.
Only rGO induced substantial adverse effects, in particular in macrophages, a type of immune cells.
Since inhalation of airborne materials is a key occupational concern, the team conducted a single exposure study in mice.
In agreement with the acute in vitro data, PA6-rGO induced a modest and transient pulmonary inflammation.
Overall this comprehensive study suggests a likely low risk to human health at acute exposure conditions of rGO-PA6.
However, further studies would be required to assess chronic effects or impact on patients suffering from chronic obstructive pulmonary disease (COPD) or asthma.
“Taken together, our study suggests a negligible impact on human health under acute exposure conditions of GRM fillers such as rGO when released from composites at doses expected at the workplace,” said lead author Dr. Peter Wick from the Swiss Federal Laboratories for Materials Science and Technology (Empa) and his colleagues.
The study was published in the Journal of Hazardous Materials.
Savvina Chortarea et al. 2022. Hazard assessment of abraded thermoplastic composites reinforced with reduced graphene oxide. Journal of Hazardous Materials 435: 129053; doi: 10.1016/j.jhazmat.2022.129053
Source link: https://www.sci.news/medicine/dust-graphene-related-materials-10924.html