TiO₂ nanoparticles (NPs) have the potential to be used in the human body as an artificial implant because of their special physicochemical properties. However, information about the effects of TiO₂ NPs on preosteoblast proliferation and osteogenic differentiation is not clear. In this work, we focus on the impact of TiO₂ NPs with different shapes and sizes on the proliferation and differentiation of MC3T3-E1 cells. The morphology and physicochemical properties of TiO₂ NPs are analyzed by scanning electron microscopy, transmission electron microscopy, Quadrasorb SI analyzer, dynamic light scattering, and zeta potential. The MTT results indicate that when the concentration of TiO₂ NPs is less than 20 μg/mL, the proliferation of osteoblasts is preserved the most. The expression of alkaline phosphatase and osteocalcin is detected by BCA and enzyme-linked immunosorbent assay to analyze the differentiation of osteoblasts. The results indicate that both rutile and anatase TiO₂ NPs have a significant inhibiting influence on the differentiation of osteoblasts. Alizarin Red staining is performed on cells to detect the mineralized nodules. The results show that TiO₂ NPs can promote the mineralization of MC3T3-E1 cells. Then, we study the oxidative stress response of MC3T3-E1 cells by flow cytometry analysis, and all TiO₂ NPs induce the excessive generation of reactive oxide species. On the other hand, our study also shows that the early apoptotic cells increase significantly. TiO₂ NPs are swallowed by cells, and then the agglomerated particles enter mitochondria, causing the shape of mitochondria to change and vacuolation to appear. All these results show that TiO₂ NPs have certain cytotoxicity to cells, but they also promote the mineralization and maturation of osteoblasts.

中文翻译：

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不同大小和形状的二氧化钛纳米颗粒的成骨潜能评估

TiO ₂纳米颗粒（NPs）具有特殊的物理化学特性，因此有可能在人体中用作人造植入物。但是，有关TiO ₂ NPs对成骨细胞增殖和成骨分化的影响的信息尚不清楚。在这项工作中，我们专注于不同形状和大小的TiO ₂ NP对MC3T3-E1细胞增殖和分化的影响。通过扫描电子显微镜，透射电子显微镜，Quadrasorb SI分析仪，动态光散射和Zeta电位分析了TiO ₂ NP的形态和理化性质。MTT结果表明，当TiO ₂ NPs的浓度小于20时 μg / mL，成骨细胞的增殖最多。通过BCA和酶联免疫吸附法检测碱性磷酸酶和骨钙素的表达，以分析成骨细胞的分化。结果表明，金红石型和锐钛矿型TiO ₂ NPs对成骨细胞的分化均具有显着的抑制作用。对细胞进行茜素红染色以检测矿化的结节。结果表明，TiO ₂ NPs可以促进MC3T3-E1细胞的矿化。然后，我们通过流式细胞仪分析了所有TiO ₂，研究了MC3T3-E1细胞的氧化应激反应NPs会引起过多的反应性氧化物。另一方面，我们的研究还表明，早期凋亡细胞显着增加。TiO ₂ NPs被细胞吞噬，然后团聚的颗粒进入线粒体，导致线粒体的形状发生改变并出现空泡。所有这些结果表明，TiO ₂ NP对细胞具有一定的细胞毒性，但它们也促进成骨细胞的矿化和成熟。