Physicochemical properties and biological activity of novel cerium oxide nanoparticles modified with pyrroloquinoline quinone

A BSTRACT Nanoscale cerium oxide (CeO2) is a bioavailable inorganic nanozyme exhibiting pronounced redox activity and capable of acting as a delivery system for bioactive compounds. We have synthesized and characterized novel CeO2 nanoparticles modified with pyrroloquinoline quinone (CeO2@PQQ). TEM analysis revealed the diameter of the CeO2@PQQ NPs to be approximately 4 nm, with a hydrodynamic diameter of 62 nm (DLS). Furthermore, the zeta potential was found to be - 38 mV (ELS), and FTIR analysis confirmed the adsorption of PQQ on the surface of CeO2 NPs. The results demonstrated that CeO2@PQQ NPs exhibited no cytotoxic effects on L929 cells within the concentration range of 0.1 - 10 mu M and did not adversely affect the mitochondrial function of the cells. It was demonstrated that CeO2@PQQ NPs exhibited protective effects against L929 cells when induced with oxidative stress (200 mu M H2O2), leading to preservation of cell mitochondrial potential levels up to 76 % of control and cell viability up to 78 % before and after incubation with CeO2@PQQ NPs. The results indicate that CeO2@PQQ NPs can be regarded as a novel hybrid nanosystem that exhibits mitochondrial-directed control of oxidative stress.