Sloan Arthur W N, Santana-Pereira Alinne L R, Goswami Joyanta, Liles Mark R, Davis Virginia A
Department of Chemical Engineering and ‡Department of Biological Sciences, Auburn University, Auburn, Alabama, United States.
Department of Chemical Engineering and Department of Biological Sciences, Auburn University, Auburn, Alabama, United States.
ACS Macro Lett. 2017 Nov 21;6(11):1228-1231. doi: 10.1021/acsmacrolett.7b00656. Epub 2017 Oct 23.
There has been little research on the dispersion of carbon nanotubes in dispersions of standard microbiological media. We report that tryptic soy broth (TSB) containing casein digest disperses single-walled carbon nanotubes (SWNT) at concentrations similar to those achieved in lysozyme (LSZ), one of the best known biomolecular SWNT dispersants. Similar to LSZ, the proposed mechanism for SWNT dispersion in TSB is favorable π-π stacking interactions with l-tryptophan. This is supported by similar SWNT concentrations in both LSZ and TSB supernatants, and the absence of appreciable dispersion in TSB that does not contain a source of l-tryptophan. Since l-tryptophan alone is insufficient to enable dispersion, it was previously hypothesized that LSZ's macromolecular structure created steric hindrance that was critical for SWNT dispersion. These new results show that intermediately sized l-tryptophan containing species can also enable dispersion. In addition, since TSB is a commonly used growth medium for microbiological research, its dispersive ability presents new research avenues for studying the effect of SWNT on prokaryotic cells without the need to oxidize SWNT or add dispersants that may induce microbial stress.
关于碳纳米管在标准微生物培养基分散体系中的分散情况，此前的研究很少。我们报告称，含有酪蛋白消化物的胰蛋白胨大豆肉汤（TSB）能够分散单壁碳纳米管（SWNT），其浓度与在溶菌酶（LSZ）中达到的浓度相似，溶菌酶是最著名的生物分子SWNT分散剂之一。与溶菌酶类似，TSB中SWNT分散的推测机制是与L-色氨酸形成有利的π-π堆积相互作用。这一点得到了LSZ和TSB上清液中相似的SWNT浓度的支持，以及不含L-色氨酸来源的TSB中没有明显分散现象的支持。由于仅L-色氨酸不足以实现分散，此前有人推测溶菌酶的大分子结构产生了对SWNT分散至关重要的空间位阻。这些新结果表明，中等大小的含L-色氨酸物种也能实现分散。此外，由于TSB是微生物研究中常用的生长培养基，其分散能力为研究SWNT对原核细胞的影响提供了新的研究途径，而无需氧化SWNT或添加可能诱导微生物应激的分散剂。
