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B75-04 Interaction of Simulated Environmental Nanoplastics (senp) With Primary Rat Alveolar Epithelial Cell Monolayers (raecm)
Summary
Scientists made lab versions of the tiny plastic particles you might actually breathe in—created by grinding up real plastic items like bottles and tubes, rather than using perfectly uniform manufactured samples typically used in research. When these particles touched lung cells grown in the lab, some types (especially those from polypropylene and PVC, common in food containers and piping) weakened the lung tissue's protective barrier function, while the particles themselves got absorbed into the cells and ended up trapped in their internal "waste disposal" compartments. This matters because it suggests that the type of plastic—not just its size—affects how much damage it might do to
Abstract Introduction Plastic pollution is readily pervasive in air and water, including submillimetric particles generated from environmental degradation. While high surface area-to-volume ratio of nanomaterials renders them efficient carriers of toxins, the biological impacts of nanoplastics <1 μm are generally not yet well understood . Most laboratory studies employed manufactured nanoplastics of uniform size and shape, which don’t necessarily reflect actual environmental plastic waste. In this study, we investigated how different nanoplastics made in-house to simulate environmental materials affect the biology of RAECM. Methods To generate seNP, we crushed and pulverized cuvettes (polystyrene (PS)), droppers (polyethylene (PE)), centrifuge tubes (polypropylene (PP)), foodservice containers (polyethylene terephthalate (PET)) and polyvinyl chloride tubes (PVC) prior to treatment with irradiation, ozonolysis and ultrasonication. We measured size distribution, surface charge and shape of these seNP using a zeta sizer and microscopic evaluation. Commercial 20 nm spherical polystyrene nanoparticles (PNP) were used for comparison. Effects of seNP and PNP on RAECM were studied by measuring transepithelial resistance (Rt) and spontaneous potential difference (PD) for up to 48h after adding 200 μg/mL of nanomaterials to apical fluid. Active ion transport (Ieq) was calculated as PD/Rt. Intracellular distribution of Nile Red-labeled seNP-PS and seNP-PVC, after 48h of apical exposure at 200 μg/mL, was investigated using confocal microscopy. Results Average size, polydispersity, morphology and zeta potential for our seNP are 120-350 nm, 11-25%, dendritic and 10-13 (±8) mV respectively. PNP exposure led to rapidly decreased Rt by ∼70% at 0.5h and a slow return to control level thereafter, whereas Ieq decreased by ∼50% at 0.5h and returned to control level very slowly. seNP-PP exposure also led to a rapid reduction in Rt by ∼30% at 0.5h and by 70% at 48 hrs, but without significant effect on Ieq. seNP-PVC exposure led to a rapid fall in Rt by ∼20% at 0.5h and to ∼30% at 48h, but without much effect on Ieq. seNP-PS, seNP-PE and seNP-PET did not cause significant changes in either Rt or Ieq following apical exposure. Nile Red-labeled seNP-PS and seNP-PVC are found in early endosomes (2.4/1.6%), autophagosomes (14.4/17.3%) and lysosomes (83.2/81.1%) after 48h of apical exposure. Conclusions These observations are consistent with the hypothesis that composition, size, shape and surface charge of nanomaterials influence their effects on the bioelectric properties of alveolar epithelium and that intracellular distribution of nanoplastics indicates uptake of nanoplastics across the alveolar epithelial cell apical membrane with subsequent activation of autophagic activity. This abstract is funded by: None