New facets of nanozyme activity of ceria: lipo- and phospholipoperoxidase-like behaviour of CeO 2 nanoparticles.

Cerium dioxide nanoparticles have a special place among engineered nanomaterials due to the wide range of their enzyme-like activities. They possess SOD-, catalase- and peroxidase-like properties, as well as recently discovered phosphatase-, photolyase-, phospholipase- and nuclease-like properties. Advancing biomedical applications of CeO 2 -based nanozymes requires an understanding of the features and mechanisms of the redox activity of CeO 2 nanoparticles when entering the vascular bed, especially when interacting with lipid-protein supramolecular complexes (biomembranes and lipoproteins). In this paper, CeO 2 nanoparticles are shown to possess two further types of nanozyme activity, namely lipo- and phospholipoperoxidase-like activities. Compared to a strong blood prooxidant, hemoglobin, CeO 2 nanoparticles act as a mild oxidising agent, since they exhibit a 10 6 times lower, and 20 times lower, prooxidant capacity towards linoleic acid and phosphatidylcholine hydroperoxides, respectively. Compared to the widespread pharmacological preparation of iron, Fe(iii) carboxymaltose (antianemic preparation Ferinject®), the prooxidant capacity of CeO 2 nanoparticles towards lipid and phospholipid substrates has been shown to be 10 2 times lower, and 4 times higher, respectively. The data obtained on the mechanism of the interaction of nanodisperse CeO 2 with the main components of biological membranes, lipids and phospholipids enable the substantial expansion of the scope of biomedical applications of CeO 2 nanozymes.