Biological activity of cerium dioxide nanoparticles.

Abstract

Cerium dioxide nanoparticles (CeO₂ NPs) with a high value of ζ-potential (≥30 mV) have been synthesized in reverse microemulsions and they are able to form the high-stable aqueous suspension without any additional stabilizers. It has been shown that the interaction of such CeO₂ NPs with transport proteins, such as BSA, affects their molecular conformation and biochemical activity. The observed changes in the UV-absorbance spectrum and intrinsic fluorescence quenching of BSA molecule are indicative of the occurrence of structural changes caused by binding with the surface of CeO₂ NPs. Low affinity between BSA and CeO₂ NPs has been confirmed by differential scanning calorimetry (DSC). Moreover, CeO₂ NPs can act as regenerative free-radical scavengers, and their antioxidant activity depends on the concentration. The positive charge of CeO₂ NPs can be attributed to their low toxicity toward human malignant lymphocytes MT-4 and breast cancer cells MCF-7 however, the morphofunctional features of MCF-7 cells interacting with CeO₂ NPs are indicative of the decrease in oncogenicity.