Effects of starch-coating of magnetite nanoparticles on cellular uptake, toxicity and gene expression profiles in adult zebrafish.

Engineered magnetite nanoparticles (Fe3O4 NPs) have been used in many fields. To prevent particle agglomeration, stabilizers or coatings are often required. While such coatings have been shown to enhance performances, the environmental impact or toxicity of stabilized or coated Fe3O4 NPs remain poorly understood. In an effort to understand the impacts of such coatings on the toxicity of Fe3O4 NPs, we used the transcriptome sequencing (RNA-seq) technique to characterize the gill and liver transcriptomes from adult zebrafish when exposed to bare and starch-stabilized Fe3O4 NPs for 7days, demonstrating remarkable differences in gene expression profiles, also known as differentially expressed genes (DEGs) profiles, in both tissues. Bare Fe3O4 NPs exerted greater toxicity than starch-coated Fe3O4 NPs in gill; in contrast, starch-Fe3O4 NPs triggered more severe damage on liver, though both bare and stabilized NPs appeared to share similar regulatory mechanisms. Quantitative real-time polymerase chain reactions using six genes each for the two tissues verified the RNA-seq results. The surface coatings play an important role in determining the nanoparticle toxicity, which in turn modulate cell uptake and biological responses, consequently impacting the potential safety and efficacy of nanomaterials.