Omics approaches in environmental effect assessment of engineered nanomaterials and nanoplastics†

Abstract

In light of the increasing application of omics technologies, such as transcriptomics, proteomics, and metabolomics, in chemical safety evaluations and interest in using these advanced tools for regulatory toxicity testing, this review critically discusses the findings from omics studies involving engineered nanomaterials and nanoplastics in aquatic and terrestrial invertebrates, unicellular organisms (cyanobacteria, fungi, microalgae and protozoa), aquatic vertebrates (fish) and crop plants. The studies published over the past nine years were analyzed based on the nanomaterial types, organism groups, and the omics approaches used, with a focus on extracting information about toxicity mechanisms. Many of these studies highlighted the role of dissolved metal ions in the toxicity of soluble metal NPs such as Ag, ZnO, Cu- and Fe-based NPs. The results generally indicate that these NPs and respective released metal ions perturb different molecular pathways, particularly in the organisms or cells that internalize NPs by endocytic mechanisms. In contrast, non-soluble metal NPs (TiO₂, CeO₂, and SiO₂ NPs) have proven relatively less acutely ecotoxic, but omics studies have revealed molecular pathway modulations, initiated by membrane interactions and cellular internalization. Overall, a common outcome of exposure to metal-based NPs is the disruption of energy metabolism. On the other hand, polymeric NPs, such as nanoplastics (primarily polystyrene NPs) tend to induce molecular-level events mainly by inducing oxidative stress. While a substantial amount of mechanistic data related to environmental nanotoxicity has been generated using omics methods, adverse outcome pathways (AOP) in ecotoxicology model organisms have only been proposed for Ag and polystyrene NPs. This indicates that new approach methodologies (NAMs) hold great potential for the safety assessment of nanomaterials in the environment, yet this potential has not been fully realized.