Toxicological Effects Of Titanium Carbide MXenes On Hyalella azteca, Zebrafish (Danio rerio), And Earthworms (Eisenia fetida).

This research investigates the environmental fate and potential toxicity of titanium carbide MXenes (Ti3C2), a class of engineered nanomaterials (ENMs), using three model organisms. MXenes are designed to be functionally 'tuned,' which enhances their capabilities, making them highly reactive nanomaterials. Although stable upon synthesis, MXenes are prone to degradation into smaller particles, which can aggregate under specific environmental conditions. To maintain stability, they are currently stored in antioxidant solutions, extending their shelf life from days to approximately six months. Due to the degradation process, it is critical to evaluate the potential environmental risks associated with MXenes before their widespread application. This research focuses on identifying potential toxic effects in Hyalella azteca, zebrafish (Danio rerio) and earthworms (Eisenia fetida). Both computational modeling and prior research suggest that MXenes degrade over time, predominantly accumulating in aquatic sediments. This makes sediment-dwelling organisms, such as Hyalella azteca, directly exposed to these nanomaterials. H. azteca, a small freshwater amphipod, was selected for toxicity testing due to its ecological role as a primary consumer at the base of the aquatic food chain, making it a potential prey species for higher trophic levels. Zebrafish (D. rerio) was chosen as a secondary model organism to evaluate bioaccumulation, as zebrafish could feed on H. azteca and share 70% of their genome with humans, making them an established model for toxicological studies. Additionally, the earthworm (E. fetida), a sentinel species in terrestrial ecosystems, was used due to MXenes' potential applications in agriculture, allowing for an evaluation of their environmental impact beyond aquatic systems. While each stage of MXene production, from laboratory synthesis to distribution, has been identified as potentially hazardous, there remains a significant gap in understanding the environmental fate and effects of MXenes, particularly given their anticipated widespread application. This research aims to address these gaps by investigating the toxicity and fate of Ti3C2 MXenes in aquatic ecosystems, focusing on H. azteca and D. rerio. By selecting both a sediment-dwelling invertebrate and its predator, the aim is to clarify the short- and long-term toxicological impacts of MXenes on different trophic levels, with an experimental design reflecting these temporal aspects. The inclusion of E. fetida in terrestrial studies further broadens the environmental scope, recognizing the potential agricultural applications of MXenes. Given the intricate interconnections between human health and environmental health, understanding the behavior and risks of these nanomaterials in natural systems is crucial. This research provides essential data for risk assessments, offering real-world insights into the environmental and ecological consequences of MXenes. It is imperative that we perform this research now, before the global deployment of large-scale MXene applications, to ensure their safety and mitigate unforeseen ecological and health risks in the interconnected ecosystems upon which all life depends.