Department of Civil and Environmental Engineering, Michigan State University, East Lansing, MI 48824, USA.
Water Res. 2010 Jan;44(2):505-20. doi: 10.1016/j.watres.2009.09.042. Epub 2009 Sep 30.
As the range of applications for carbon nanotubes (CNTs) rapidly expands, understanding the effect of CNTs on prokaryotic and eukaryotic cell systems has become an important research priority, especially in light of recent reports of the facile dispersion of CNTs in a variety of aqueous systems including natural water. In this study, single-walled carbon nanotubes (SWCNTs) were dispersed in water using a range of natural (gum arabic, amylose, Suwannee River natural organic matter) and synthetic (polyvinyl pyrrolidone, Triton X-100) dispersing agents (dispersants) that attach to the CNT surface non-covalently via different physiosorption mechanisms. The charge and the average effective hydrodynamic diameter of suspended SWCNTs as well as the concentration of exfoliated SWCNTs in the dispersion were found to remain relatively stable over a period of 4 weeks. The cytotoxicity of suspended SWCNTs was assessed as a function of dispersant type and exposure time (up to 48 h) using general viability bioassay with Escherichia coli and using neutral red dye uptake (NDU) bioassay with WB-F344 rat liver epithelia cells. In the E. coli viability bioassays, three types of growth media with different organic loadings and salt contents were evaluated. When the dispersant itself was non-toxic, no losses of E. coli and WB-F344 viability were observed. The cell viability was affected only by SWCNTs dispersed using Triton X-100, which was cytotoxic in SWCNT-free (control) solution. The epigenetic toxicity of dispersed CNTs was evaluated using gap junction intercellular communication (GJIC) bioassay applied to WB-F344 rat liver epithelial cells. With all SWCNT suspensions except those where SWCNTs were dispersed using Triton X-100 (wherein GJIC could not be measured because the sample was cytotoxic), no inhibition of GJIC in the presence of SWCNTs was observed. These results suggest a strong dependence of the toxicity of SWCNT suspensions on the toxicity of the dispersant and point to the potential of non-covalent functionalization with non-toxic dispersants as a method for the preparation of stable aqueous suspensions of biocompatible CNTs.
随着碳纳米管（CNTs）应用范围的迅速扩大，了解 CNTs 对原核和真核细胞系统的影响已成为一项重要的研究重点，特别是鉴于最近有报道称 CNTs 很容易在包括天然水在内的各种水相体系中分散。在这项研究中，使用一系列天然（阿拉伯胶、直链淀粉、苏旺尼河天然有机物）和合成（聚乙烯吡咯烷酮、Triton X-100）分散剂（分散剂）将单壁碳纳米管（SWCNTs）分散在水中，这些分散剂通过不同的物理吸附机制非共价地附着在 CNT 表面上。发现悬浮 SWCNTs 的电荷量和平均有效水动力直径以及分散体中剥离的 SWCNTs 的浓度在 4 周的时间内相对稳定。使用大肠杆菌的一般生存能力生物测定法和 WB-F344 大鼠肝上皮细胞的中性红染料摄取（NDU）生物测定法，评估了悬浮 SWCNTs 的细胞毒性，作为分散剂类型和暴露时间（长达 48 小时）的函数。在大肠杆菌生存能力生物测定中，评估了三种具有不同有机负荷和盐含量的生长培养基。当分散剂本身无毒时，大肠杆菌和 WB-F344 的存活率没有降低。只有使用 Triton X-100 分散的 SWCNTs 才会影响细胞活力，而在不含 SWCNT（对照）的溶液中 Triton X-100 是有毒的。使用适用于 WB-F344 大鼠肝上皮细胞的缝隙连接细胞间通讯（GJIC）生物测定法评估分散 CNTs 的表观遗传毒性。除了使用 Triton X-100 分散的 SWCNT 悬浮液（其中由于样品有毒，无法测量 GJIC）之外，所有 SWCNT 悬浮液中均未观察到 SWCNTs 存在时 GJIC 的抑制。这些结果表明，SWCNT 悬浮液的毒性强烈依赖于分散剂的毒性，并指出使用无毒分散剂进行非共价功能化作为制备生物相容 CNTs 稳定水相悬浮液的方法具有潜力。
