170079 20260316092630.0 doi 10.1016/j.impact.2025.100608 sideral 148605 ART-2025-148605 eng Bakir, Mariam Impact of titanium dioxide and cerium dioxide nanoparticle mixtures on the green alga Raphidocelis subcapitata 2025 Engineered nanoparticles (NPs) occur as mixtures in the environment, making the study of their combined toxicity more realistic than the assessment of individual NPs. Interactions between NPs can alter toxicity profiles, producing synergistic, antagonistic, or additive effects, yet current environmental assessments often overlook these cocktail effects. This study investigated the effects of titanium dioxide NPs (TiO2-NPs) and cerium dioxide NPs (CeO2-NPs) mixtures on the green alga Raphidocelis subcapitata compared individual NP exposures. Four mixtures with varying NP ratios were designed based on the toxicity units (TUs) concept and EC₅₀ growthinhibition values for TiO2-NPs of 28.3 ± 1.16 mg L− 1 , and EC50 for CeO2-NPs of 13.6 ± 0.57 mg L− 1 . Growth inhibition, reactive oxygen species (ROS) generation, and membrane damage were assessed using flow cytometry (FCM), while uptake was analyzed by single-cell inductively coupled plasma mass spectrometry (SC-ICP-MS). Single-particle (SP) -ICP-MS distinguished NP size distribution and dissolution in mixtures. Results revealed antagonistic interactions in mixtures, with growth inhibition lower than expected based on individual treatments. The difference between predicted and measured TUs in the mixture treatments, used as a measure for the extent of antagonistic interaction ranged from 0.66 to 1.76. Cells with elevated ROS generation showed a two- to four-fold reduction in the mixtures versus single NP treatments. SC-ICP-MS indicated reduced bioavailability of NPs in mixtures: intracellular TiO₂-NP content decreased from 15.7 to 24.3 fg cell− 1 (single) to 12.9–15.9 fg cell− 1 (mixture), and CeO₂-NP content dropped from 3.6 to 8.6 fg cell− 1 to 2.7–3.8 fg cell− 1 . This study demonstrates the importance of assessing NP mixture toxicity using advanced single-event techniques, such as FCM, SP- and SC-ICP-MS, to discriminate the fate and bioavailability of NPs present in mixtures and to better understand their environmental impacts. Access copy available to the general public Unrestricted info:eu-repo/grantAgreement/ES/DGA/E29-23R info:eu-repo/grantAgreement/ES/MICINN/PID2021-123203OB-I00 info:eu-repo/grantAgreement/ES/NextGenerationEU/MZ-240621 info:eu-repo/semantics/openAccess by https://creativecommons.org/licenses/by/4.0/deed.es info:eu-repo/semantics/article info:eu-repo/semantics/publishedVersion Abad-Alvaro, Isabel Universidad de Zaragoza (orcid)0000-0002-4169-0357 Laborda, Francisco Universidad de Zaragoza (orcid)0000-0002-7931-3901 Slaveykova, Vera I. 2009 750 Universidad de Zaragoza Dpto. Química Analítica Área Química Analítica 41 (2025), 100608 [10 pp.] NanoImpact 2452-0748 2245974 http://zaguan.unizar.es/record/170079/files/texto_completo.pdf Versión publicada 2516365 http://zaguan.unizar.es/record/170079/files/texto_completo.jpg?subformat=icon icon Versión publicada oai:zaguan.unizar.es:170079 articulos driver 2026-03-16-08:18:13 ARTICLE