Single-Cell Transcriptomic Analysis Reveals Hair Cell-Specific Molecular Responses to Polystyrene Nanoplastics in a Zebrafish Embryo Model.

Polystyrene nanoplastics (PSNPs) have emerged as pervasive environmental pollutants with potential toxicological effects on aquatic ecosystems. Their small size, hydrophobicity, and structural stability enable penetration into biological tissues, inducing diverse toxic responses. This study investigates the physiological and molecular impacts of PSNPs on zebrafish embryos using single-cell RNA sequencing and phenotypic analyses. While PS-NP exposure at environmentally relevant concentrations caused no significant changes in survival or overt phenotypes, it led to alterations in cell type proportions and gene expression. Differentially expressed gene (DEG) analysis revealed the upregulation of genes such as col1a1a, fgfbp2b, cytl1, and fstl1a, which were validated in vivo. These genes are associated with extracellular matrix remodeling, immune regulation, and tissue repair, suggesting that PSNPs activate defensive and reparative mechanisms in response to environmental stress. These findings highlight the molecular and cellular responses to PSNP exposure in zebrafish embryos and underscore the importance of evaluating the ecological risks posed by nanoplastics.