Nano-TiO₂ removal using jellyfish extracts and an assessment of aquatic toxicity

Background: Nano-TiO₂ is a material used in various industries, and its usage is increasing every year. It is a concern that it is a potential ecotoxic substance because it flows into rivers after use. Since the material extracted from jellyfish as a biological material has the ability to capture nanomaterials, its possibility needs to be confirmed. Objective: In this study, we used material extracted using the immune response of jellyfish (JEl) to capture N-TiO₂ and confirm its capture ability and whether it has ecotoxicity. Results: JEI bound to 61.94% of the total N- TiO₂ administered after 0.5 h and maintained 73.29% of the binding capacity of N-TiO₂ 4 h after administration. The abnormality rate of the JEI-exposed group was 3.39 ± 3.99%, which was not different from that of the control group, while the N-TiO₂ exposure group showed an abnormality rate of 33.75 ± 13.77%. The abnormality rate of N-TiO₂ + JEI (11.36 ± 8.10%) was 3 times lower than that of the N-TiO₂ group. In the apoptosis test, the groups exposed to JEI and N-TiO₂ + JEI showed significant decreases in fluorescence (9.11-fold and 7.62-fold, respectively), compared to the group exposed to N-TiO₂ alone (P < 0.001). In the group exposed to N-TiO₂, the transcript-level expression of stc2a, which is involved in cell homeostasis, was increased by more than twofold, whereas that of slc30a10, slc34a2b, slc31a1, ham, and pck1 was decreased by more than twofold. In contrast, the transcript-level expression of genes in the group exposed to N-TiO₂ + JEI ranged from 0.320 to 1.194. Conclusion: JEI not only captured N-TiO₂ in a short period of time, but also showed no aquatic ecosystem toxicity and no genotoxicity.