Cerium dioxide nanoparticles (CeO2NP) show antioxidant enzyme-mimetic properties and ROS scavenging activity, making them a promising material for nanomedicine, although their potential adverse effects are not totally understood yet. The objective of this work was to assess the biological behaviour of CeO2NP in human neuronal SH-SY5Y and glial A172 cells. After carrying out the physical-chemical characterization of the CeO₂NP and analysing their ability to be taken up by neuronal and glial cells, the possible alterations in cell viability and the induction of DNA double strand breaks was determined in the presence of these NP by means of MTT assay and γH2AX assay, respectively. The possible existence of interference of the NP with the assay methodologies was previously addressed and corrected when necessary. The results obtained showed that, even though there was a significant dose- and time-dependent internalization of the NP by both cell lines, the CeO₂NP generally presented scarce cyto- or genotoxicity, essentially depending on the NP exposure time and being restricted to higher doses. These results provide a better understanding of CeO₂NP interaction with cellular systems and their possible adverse effects, specifically at the level of the nervous system. These data may be used in risk assessment of exposure to these NP, and as a basis for establishing good practice guidelines for their management, in addition to contributing to increase the knowledge about the impact of CeO₂NP on human health.

Funding: Ministry of Science and Innovation: MCIN/AEI/10.13039/501100011033 (Grant PID2020-114908GA-I00), Xunta de Galicia (ED431B 2022/16), CICA-Disrupting Project 2021SEM‐B2, Ministry of Education, Culture and Sport [BEAGAL18/00142 to V.V.], and FCT [SFRH/BPD/122112/2016 to A.T.R]. This communication is based upon work from COST Action "Nano2Clinic" CA17140, supported by COST (European Cooperation in Science and Technology).