Batiuskaite Danute, Bruzaite Ingrida, Snitka Valentinas, Ramanavicius Arunas
Department of Biology, Faculty of Natural Sciences, Vytautas Magnus University, 58 K. Donelaicio Str., LT-44248 Kaunas, Lithuania.
Department of Chemistry and Bioengineering, Faculty of Fundamental Sciences, Vilnius Gediminas Technical University, Sauletekio Av. 11, LT-10223 Vilnius, Lithuania.
Materials (Basel). 2022 Jun 29;15(13):4570. doi: 10.3390/ma15134570.
The process of nanoparticles entering the cells of living organisms is an important step in understanding the influence of nanoparticles on biological processes. The interaction of nanoparticles with the cell membrane is the first step in the penetration of nanoparticles into cells; however, the penetration mechanism is not yet fully understood. This work reported the study of the interaction between TiO nanoparticles (TiO-NPs) and Chinese hamster ovary (CHO) cells using an in vitro model. The characterization of crystalline phases of TiO NPs was evaluated by transmission electron microscopy (TEM), X-ray diffraction (XRD) spectrum, and atomic force microscopy (AFM). Interaction of these TiO nanoparticles (TiO- NPs) with the CHO cell membrane was investigated using atomic force microscopy (AFM) and Raman spectroscopy. The XRD analysis result showed that the structure of the TiO particles was in the rutile phase with a crystallite size of 60 nm, while the AFM result showed that the particle size distribution had two peaks with 12.1 nm and 60.5 nm. The TEM analysis confirmed the rutile phase of TiO powder. Our study showed that exposure of CHO cells to TiO-NPs caused morphological changes in the cell membranes and influenced the viability of cells. The TiO-NPs impacted the cell membrane surface; images obtained by AFM revealed an 'ultra structure' with increased roughness and pits on the surface of the membrane. The depth of the pits varied in the range of 40-80 nm. The maximal depth of the pits after the treatment with TiO-NPs was 100% higher than the control values. It is assumed that these pits were caveolae participating in the endocytosis of TiO-NPs. The research results suggest that the higher maximal depth of the pits after the exposure of TiO-NPs was determined by the interaction of these TiO-NPs with the cell's plasma membrane. Moreover, some of pits may have been due to plasma membrane damage (hole) caused by the interaction of TiO-NPs with membrane constituents. The analysis of AFM images demonstrated that the membrane roughness was increased with exposure time of the cells to TiO-NPs dose. The average roughness after the treatment for 60 min with TiO-NPs increased from 40 nm to 78 nm. The investigation of the membrane by Raman spectroscopy enabled us to conclude that TiO-NPs interacted with cell proteins, modified their conformation, and potentially influenced the structural damage of the plasma membrane.
纳米颗粒进入活生物体细胞的过程是理解纳米颗粒对生物过程影响的重要一步。纳米颗粒与细胞膜的相互作用是纳米颗粒进入细胞的第一步；然而，其渗透机制尚未完全明确。本研究报道了利用体外模型对二氧化钛纳米颗粒（TiO-NPs）与中国仓鼠卵巢（CHO）细胞之间相互作用的研究。通过透射电子显微镜（TEM）、X射线衍射（XRD）光谱和原子力显微镜（AFM）对TiO纳米颗粒的晶相进行了表征。利用原子力显微镜（AFM）和拉曼光谱研究了这些二氧化钛纳米颗粒（TiO-NPs）与CHO细胞膜的相互作用。XRD分析结果表明，TiO颗粒的结构为金红石相，微晶尺寸为60nm，而AFM结果表明，粒径分布有两个峰值，分别为12.1nm和60.5nm。TEM分析证实了TiO粉末的金红石相。我们的研究表明，CHO细胞暴露于TiO-NPs会导致细胞膜形态变化，并影响细胞活力。TiO-NPs对细胞膜表面产生影响；AFM获得的图像显示，膜表面出现粗糙度增加和凹坑的“超微结构”。凹坑深度在40-80nm范围内变化。用TiO-NPs处理后凹坑的最大深度比对照值高100%。推测这些凹坑是参与TiO-NPs内吞作用的小窝。研究结果表明，TiO-NPs暴露后凹坑的最大深度较高是由这些TiO-NPs与细胞质膜的相互作用决定的。此外，一些凹坑可能是由于TiO-NPs与膜成分相互作用导致的质膜损伤（孔洞）。对AFM图像的分析表明，随着细胞暴露于TiO-NPs剂量时间的增加，膜粗糙度增加。用TiO-NPs处理60分钟后，平均粗糙度从40nm增加到78nm。通过拉曼光谱对膜进行研究使我们能够得出结论，TiO-NPs与细胞蛋白相互作用，改变其构象，并可能影响质膜的结构损伤。
