Detection and Inhalation Hazard Assessment of Wear Particles Arising From Abrasion of Market‐relevant Graphene Reinforced Composites

Commercial products incorporating graphene-based two-dimensional (2D) nanosheets are increasingly developed to enhance mechanical, thermal, and electrical performance. Potential release of inhalable particles during manufacturing or end-of-life processing, however, raises concerns regarding respiratory health. This study explored the pulmonary cytotoxicity and immunomodulatory activity of airborne particles generated by mechanical abrasion of industrially relevant few-layer graphene (FLG) reinforced epoxy composites. A multimodal analytical strategy combining high-resolution transmission electron microscopy, Raman microscopy, and time-of-flight secondary ion mass spectrometry enabled reliable detection and spatial mapping of FLG in pristine and abraded composites. Abrasion predominantly produced composite fragments in which FLG remained embedded, with no indication of protruding or freely released FLG nanosheets. Across advanced bronchial and alveolar epithelial air-liquid interface models, neither abraded epoxy nor FLG-epoxy particles induced cytotoxic or pro-inflammatory responses. A moderate reduction of mucociliary clearance was observed only at high exposure doses of abraded epoxy particles, without amplification by FLG reinforcement. As-produced FLG triggered strong TNF-α secretion in alveolar macrophages, whereas abraded FLG-epoxy particles elicited minimal responses. Overall, the findings indicate limited acute respiratory toxicity associated with inhalation of fragments released from FLG-based epoxy composites under production and end-of-life scenarios.