Biological activity of cerium dioxide nanoparticles.

Cerium dioxide nanoparticles (CeO 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 CeO 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 CeO NPs. Low affinity between BSA and CeO NPs has been confirmed by differential scanning calorimetry (DSC). Moreover, CeO NPs can act as regenerative free-radical scavengers, and their antioxidant activity depends on the concentration. The positive charge of CeO 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 CeO NPs are indicative of the decrease in oncogenicity.