Herein, single-walled carbon nanotubes (SWCNTs) were synthesized by the thermal chemical vapor deposition (CVD) method, and characterized by scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX), transmission electron microscopy (TEM), Raman spectroscopy, dynamic light scattering (DLS), and thermo-gravimetric analysis (TGA). The results indicated that obtained nanotubes were SWCNTs with high crystallinity and their average diameter was 10.15 ± 3 nm. Allium cepa ana–telophase and comet assays on the root meristem were employed to evaluate the cytotoxic and genotoxic effects of SWCNTs by examining mitotic phases, mitotic index (MI), chromosomal aberrations (CAs), and DNA damage. A. cepa root tip cells were exposed to SWCNTs at concentrations of 12.5, 25, 50, and 100 μg/ml for 4 h. Distilled water and methyl methanesulfonate (MMS, 10 μg/ml) were used as the negative and positive control groups, respectively. It was observed that MIs decreased statistically significantly for all applied doses. Besides, CAs such as chromosome laggards, disturbed anaphase–telophase, stickiness and bridges and also DNA damage increased in the presence of SWCNTs in a concentration-dependent manner. In the molecular docking study, the SWCNT were found to be a strong DNA major groove binder showing an energetically very favorable binding free energy of −21.27 kcal/mol. Furthermore, the SWCNT interacted effectively with the nucleotides on both strands of DNA primarily via hydrophobic π and electrostatic interactions. As a result, cytotoxic and genotoxic effects of SWCNTs in A. cepa root meristematic cells which is a reliable system for assessment of nanoparticle toxicology were demonstrated in this study.

中文翻译：

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单壁碳纳米管的合成与表征：洋葱根尖细胞遗传毒性和分子对接研究

本文采用热化学气相沉积 (CVD) 方法合成单壁碳纳米管 (SWCNT)，并通过扫描电子显微镜 (SEM)、能量色散 X 射线光谱 (EDX)、透射电子显微镜 (TEM) 对其进行表征。 、拉曼光谱、动态光散射 (DLS) 和热重分析 (TGA)。结果表明，所获得的纳米管是具有高结晶度的单壁碳纳米管，其平均直径为10.15±3 nm。通过检查有丝分裂期、有丝分裂指数 (MI)、染色体畸变 (CA) 和 DNA 损伤，对根分生组织进行洋葱 cepa ana-telophase 和彗星测定以评估 SWCNT 的细胞毒性和遗传毒性作用。A. cepa根尖细胞以 12.5、25、50 和 100 μg/ml 的浓度暴露于 SWCNTs 4 小时。蒸馏水和甲磺酸甲酯（MMS，10 μg/ml）分别用作阴性和阳性对照组。观察到所有应用剂量的 MI 在统计学上显着降低。此外，在单壁碳纳米管的存在下，染色体滞后、受干扰的后期-末期、粘性和桥接以及 DNA 损伤等 CAs 以浓度依赖性方式增加。在分子对接研究中，发现 SWCNT 是一种强大的 DNA 大沟粘合剂，显示出能量非常有利的结合自由能 -21.27 kcal/mol。此外，SWCNT 主要通过疏水 π 和静电相互作用与 DNA 两条链上的核苷酸有效相互作用。因此，A. cepa根分生细胞是评估纳米颗粒毒理学的可靠系统，在本研究中得到证实。