Engineered Nanoparticle Transformations: Rethinking Toxicity in Water

The increased production and use of engineered nanoparticles (ENPs) have led to their release into the environment. Research has examined their physical, chemical, and biological transformations and the environmental factors influencing these processes. However, understanding these transformations in complex systems, especially around organisms, remains incomplete. Transformations significantly alter ENP properties, affecting their interactions with organisms by enhancing penetration of biological barriers and activation of signaling pathways. These interactions depend on ENP properties like size, shape, surface area, and chemical composition. Recently, studies have focused on the toxicity of transformed ENPs, which generally exhibit lower toxicity than pristine counterparts due to reduced dissolution and limited direct cell contact. Most studies have examined acute toxicity, leaving long-term effects unknown. Future research should explore toxicity mechanisms, environmental influences, and competing transformation processes, potentially using machine learning (ML) and artificial intelligence (AI). This review synthesizes current knowledge on the fate and toxicity of transformed ENPs, assesses ecological risks in aquatic environments, and identifies knowledge gaps to guide future research. Filling data gaps is essential for effective use of AI tools in modeling ENP-environment interactions.