Titanium dioxide nanoparticles (TiO2 NPs) are widely used in photodynamic therapy (PDT) of cancer treatment as excellent regenerative photocatalysts. However, there are some challenges because of their poor dispersity. Transferrin (Tf) was tried to modify the surface of TiO2 NPs to reduce the aggregation, which further affected uptake and excretion on SMMC-7721 human liver cancer cells. Initially, TiO2 NPs modified with Tf (TiO2-Tf NPs) entered into the cells faster than the pure TiO2 NPs which remain attaching on the cell membrane after short-term co-incubation. Tf modification increased the rate and amount of cellular endocytosis. Both TiO2 NPs and TiO2-Tf NPs were observed in lysosomes after long-term co-incubation through clathrin-mediated endocytosis pathway. Expulsion of NPs was then observed and it was found that the exocytosis of TiO2-Tf NPs was fast in the first 24 h, and then slowed down gradually from 24 h to 144 h. Totally, existence of Tf decreased the exocytosis of TiO2 NPs. Furthermore, the differences of cytotoxicity and genotoxicity between TiO2 NPs and TiO2-Tf NPs show that surface-adsorbed Tf components provide some protection from the cytotoxic effect by reducing the production of intracellular ROS. TiO2-Tf NPs obviously affected cell cycle, indicating a significant G2/M phase cell cycle arrest. Our results offer a promising application of easily aggregated TiO2 NPs in the nanomedicine field.

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转铁蛋白对二氧化钛纳米颗粒细胞摄取或排出的影响

二氧化钛纳米粒子（TiO2NPs）作为优异的再生光催化剂被广泛用于癌症治疗的光动力疗法（PDT）。然而，由于它们的分散性差，存在一些挑战。转铁蛋白 (Tf) 试图修饰 TiO2 的表面2NPs 可减少聚集，从而进一步影响 SMMC-7721 人肝癌细胞的摄取和排泄。最初，二氧化钛2用 Tf 修饰的 NPs (TiO2-Tf NPs）比纯二氧化钛更快地进入细胞2短期共孵育后仍附着在细胞膜上的 NP。Tf 修饰增加了细胞内吞的速率和数量。二氧化钛2纳米粒子和二氧化钛2在通过网格蛋白介导的内吞途径长期共孵育后，在溶酶体中观察到 -Tf NPs。然后观察到 NPs 的排出，发现 TiO2 的胞吐作用2-Tf NPs 在前 24 小时内较快，然后从 24 小时到 144 小时逐渐减慢。总而言之，Tf 的存在降低了 TiO2 的胞吐作用2NP。此外，TiO 之间的细胞毒性和遗传毒性的差异2纳米粒子和二氧化钛2-Tf NPs 表明，表面吸附的 Tf 组分通过减少细胞内 ROS 的产生来提供一些免受细胞毒性作用的保护。二氧化钛2-Tf NPs 明显影响细胞周期，表明显着的 G2/M 期细胞周期停滞。我们的研究结果为易于聚集的 TiO2 提供了有前景的应用2纳米医学领域的纳米粒子。