Teabag-derived micro/nanoplastics (true-to-life MNPLs) as a surrogate for real-life exposure scenarios.

The potential health implications of environmental micro/nanoplastics (MNPLs) are increasingly concerning. Beyond environmental exposure, other sources such as food packaging, including herbal/teabags, may also be significant. This study investigates the release of MNPLs from three commercially available teabags. By simulating tea preparation, MNPL samples were extracted and characterized using a range of analytical techniques: scanning electron microscopy (SEM), transmission electron microscopy (TEM), attenuated total reflectance/Fourier transform infrared spectroscopy (ATR-FTIR), dynamic light scattering (DLS), laser Doppler velocimetry (LDV), and nanoparticle tracking analysis (NTA). The results confirmed that the teabags were made of nylon-6 (NY6), polypropylene (PP), and cellulose (CL) and that microfibers and nano-range particles (NPLs) were present in the leachates. NTA data revealed that the number of released NPLs was 1.20 × 10 ⁹ /mL (PP; 136.7 nm), 1.35 × 10 ⁸ /mL (CL; 244 nm), and 8.18 × 10 ⁶ /mL (NY6; 138.4). The leachate particles were then stained with iDye Poly-Pink and used to expose three human intestine-derived cell types (Caco-2, HT29, and HT29-MTX) to assess their biointeractions and the role of the mucosubstances in vitro. The results demonstrated that after 24 h of exposure to 100 μg/mL NPLs, there was significant uptake of PP-NPLs in HT29-MTX cells, as a model of cells segregating high amount of mucus. A similar uptake was observed for CL-NPLs in HT29 and HT29-MTX cells, while NY6-NPLs were internalized preferentially in Caco-2 cells. These findings underscore the importance of identifying new environmentally relevant MNPL exposure sources, for developing realistic MNPLs samples, and further investigating their potential human health effects.
Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.
(Copyright © 2024 The Author(s). Published by Elsevier Ltd.. All rights reserved.)