Study On Mechanism Of NaYF₄:Eu³⁺ Nanoparticles Induced Liver Cells Apoptosis

Because of the unique optical properties, rare-earth doped sodium yttrium fluoride?NaYF₄? nanoparticles have potential applications in the biomedical field. However, the potential hazards to human health can not been ignored. In order to study the biological effects of nanoparticles on cells, europium-doped NaYF₄(NaYF₄:Eu³⁺) nanoparticles were prepared by the hydrothermal method in this study, and the BRL 3A liver cells were chosen as the cell model. All three sized as-prepared particles appeared nearly spherical shape with average diameters of 52 ± 6.82, 148 ± 14.32, and 344 ± 46.21 nm, respectively. Their phase were the cubic crystalline phase, and europium was doped into these crystal lattices,effectively. These particles had fluorescent properties, with maximum excitation and emission wavelengths of 394 and 594 nm, respectively. The ingestion mechanism experiments confirmed that NaYF₄:Eu³⁺ nanoparticles could enter into liver cells by an energy-dependent endocytosis way. MTT assay demonstrated that the cytotoxicity was time- and sizedependent. These nanoparticles could damage the structure of cell membrane, which caused leakage of LDH from cytoplasm to culture medium. Three sizes of NaYF₄:Eu³⁺ nanoparticles induced apoptosis by the experiments of Annexin V-FITC/PI and AO/EB double staining.Apart from the elevation malondialdehyde elevated, the decrease of superoxide dismutase,glutathione peroxidase and catalase activity indicated intracellular accumulation of reactive oxygen species, which were associated with oxidative stress. In addition, mitochondria damage was confirmed by reduction of mitochondrial membrane potential. The increase of Bid, Bax and Caspase 3 activity indicated apoptosis. Therefore, NaYF₄:Eu³⁺ nanoparticles could lead to liver cells of oxidative stress and mitochondria damage, apoptosis-related proteins were activated, ultimately result in cell apoptosis.