Gheshlaghi Zahra Naghdi, Riazi Gholam Hossein, Ahmadian Shahin, Ghafari Mahmoud, Mahinpour Roya
Institute of Biochemistry and Biophysics, Department of Biochemistry, University of Tehran, Tehran 13145-1384, Iran.
Acta Biochim Biophys Sin (Shanghai). 2008 Sep;40(9):777-82.
Titanium dioxide (TiO2) nanoparticles (NPs) are widely used in several manufactured products. The small size of NPs facilitates their uptake into cells as well as transcytosis across epithelial cells into blood and lymph circulation to reach different sites, such as the central nervous system. Different studies have shown the risks that TiO2 NPs in the neuronal system and other organs present. As membrane-bound layer aggregates or single particles, TiO2 NPs can enter not only cells, but also mitochondria and nuclei. Therefore these particles can interact with cytoplasmic proteins such as microtubules (MTs). MTs are cytoskeletal proteins that are essential in eukaryotic cells for a variety of functions, such as cellular transport, cell motility and mitosis. MTs in neurons are used to transport substances such as neurotransmitters. Single TiO2 NPs in cytoplasm can interact with these proteins and affect their crucial functions in different tissues. In this study, we showed the effects of TiO2 NPs on MT polymerization and structure using ultraviolet spectrophotometer and fluorometry. The fluorescent spectroscopy showed a significant tubulin conformational change in the presence of TiO2 NPs and the ultraviolet spectroscopy results showed that TiO2 NPs affect tubulin polymerization and decrease it. The aim of this study was to find the potential risks that TiO2 NPs pose to human organs and cells.
二氧化钛（TiO₂）纳米颗粒（NPs）广泛应用于多种制成品中。纳米颗粒的小尺寸便于它们被细胞摄取，并通过上皮细胞进行转胞吞作用进入血液和淋巴循环，从而到达不同部位，如中枢神经系统。不同研究已表明二氧化钛纳米颗粒在神经系统和其他器官中存在的风险。作为膜结合层聚集体或单个颗粒，二氧化钛纳米颗粒不仅可以进入细胞，还能进入线粒体和细胞核。因此，这些颗粒可以与细胞质蛋白如微管（MTs）相互作用。微管是细胞骨架蛋白，在真核细胞中对多种功能至关重要，如细胞运输、细胞运动和有丝分裂。神经元中的微管用于运输诸如神经递质等物质。细胞质中的单个二氧化钛纳米颗粒可以与这些蛋白质相互作用，并影响它们在不同组织中的关键功能。在本研究中，我们使用紫外分光光度计和荧光测定法展示了二氧化钛纳米颗粒对微管聚合和结构的影响。荧光光谱显示在二氧化钛纳米颗粒存在的情况下微管蛋白构象发生了显著变化，紫外光谱结果表明二氧化钛纳米颗粒影响微管蛋白聚合并使其减少。本研究的目的是找出二氧化钛纳米颗粒对人体器官和细胞造成的潜在风险。
