Polytetrafluoroethylene utensils as a source of micro- and nanoplastics: Insights from a Drosophila model

Polytetrafluoroethylene (PTFE), widely used in household products and cookware, can release particles into food, posing potential health risks. The biological interactions of the resulting micro- and nanoplastics (MNPLs) remain poorly understood but can be clarified by linking structural and physiological effects with transcriptomic changes. Here, Drosophila was used as an in vivo model to assess size-dependent responses to PTFE micro- (MPLs) and nanoscale (NPLs) particles. Following oral exposure, PTFE-MNPLs accumulated in the midgut lumen and interacted with gut components, leading to particle erosion, fragmentation, and the release of secondary ultrafine particles. Internalised particles adhered to and damaged gut bacteria, penetrated the intestinal barrier, and compromised epithelial integrity by impairing microvilli, lysosomes, and mitochondria, ultimately entering circulation and interacting with haemocytes. Associated physiological disturbances, including oxidative stress, mitochondrial membrane depolarization, and DNA damage, were reflected in transcriptomic and RT-qPCR analyses, revealing coordinated molecular alterations underlying the observed tissue damage. Analysis also revealed extensive size- and concentration-dependent gene expression changes, with up to 2897 differentially expressed genes for NPLs and a core set of 110 genes consistently affected across treatments, highlighting the common molecular impact of PTFE-MNPL exposure. These genes were enriched in pathways governing metabolism, mitochondrial function, redox balance, immunity, neurodegeneration, apoptosis, intracellular trafficking, and cell migration. Our findings provide a comprehensive view of MNPLs' biological interactions, linking their physical properties to physiological effects across multiple levels and supported by transcriptomic analysis, particularly for the poorly studied PTFE particles.