Teabag-derived microplastics pose steatosis and oxidative stress-mediated toxicity in embryonic zebrafish

Microplastics released from consumer products, such as teabags, are an emerging environmental and health concern. Teabag-derived microplastics (TMPs) represent a significant yet underexplored source of micropollutants. This study investigated the developmental and molecular toxicity of TMPs in zebrafish embryos through integrated experimental and computational approaches. TMPs extracted from commercial teabags had a mean hydrodynamic diameter of 389.7 nm and a zeta potential of -59.4 mV, indicating high colloidal stability. Embryos exposed to TMPs exhibited dose-dependent developmental abnormalities, with up to 45 % mortality and over 30 % incidence of pericardial edema and notochord defects at higher concentrations. ROS levels increased significantly (p < 0.0001), accompanied by lipid droplet accumulation, indicating steatosis. Gene expression analysis showed marked upregulation of Zhe1 (>10-fold), Sod1 (>12-fold), and Tp53 (∼4.5-fold), reflecting hatching stress, oxidative imbalance, and apoptosis. Flow cytometry confirmed elevated acridine orange-positive apoptotic cells. Molecular docking revealed strong binding affinity of styrene, a leachate from TMPs, to Zhe1, Sod1, and p53, with Sod1 showing the highest affinity (-5.4 kcal/mol). These findings suggest TMPs toxicity results not only from physical exposure but also from specific molecular interactions. The study underscores the urgent need to evaluate the risks of microplastic leachates from food-contact materials.