55 Inhalation hazard of graphene-enabled composite materials during manufacture and degradation of market-relevant products

Abstract Two-dimensional (2D) graphene-based advanced materials are increasingly utilized across a wide range of applications, including battery technology, superconductors, biomedical products, and catalysis. As their use expands, so does the potential for human exposure, particularly in occupational environments during production, as well as during end-of-life handling. Inhalation represents a major route of exposure for workers in these settings. Here, we aimed to investigate potential inhalation-related health hazards of few-layer graphene (FLG; Carbon Waters)-epoxy composites using alveolar macrophages (NR8383) and ALIsens, AlveolAirTM and MucilAirTM advanced in vitro lung cell culture models. The results demonstrate successful detection of FLG in the epoxy (product) matrix by using Raman spectroscopy and time-of-flight secondary ion mass spectrometry (TOF-SIMS) techniques. The alveolar macrophage assay demonstrated material-specific variations in bioresponse. Pristine FLG did not impact macrophage viability but induced a pronounced secretion of the pro-inflammatory cytokine TNFα. In contrast, particles collected after abrasion of FLG-epoxy composites showed no significant upregulation in TNFα response but induced dose-dependent cytotoxicity in alveolar macrophages. In the bronchial and alveolar airway epithelial cultures, pristine FLG and abraded particles did not decrease cell viability or compromise barrier integrity, but a moderate reduction of mucociliary clearance was observed at concentrations above 10 µg/cm2, which was further confirmed with scanning electron microscopy (SEM). Overall, our data reveals distinct health risks associated with particle inhalation during FLG-epoxy composite production and degradation, affecting multiple lung cell types. These findings provide valuable mechanistic insights to support health hazard assessment and safe-by-design development of industrial graphene-based composite materials.