Department of Physics, Graduate School of Science, Tokyo University of Science, 1-3 Kagurazaka, Shinjuku, Tokyo 1628601, Japan.
Department of Physics, Graduate School of Science, Tokyo University of Science, 1-3 Kagurazaka, Shinjuku, Tokyo 1628601, Japan.
Colloids Surf B Biointerfaces. 2018 Dec 1;172:684-689. doi: 10.1016/j.colsurfb.2018.09.026. Epub 2018 Sep 13.
We detected antioxidant activity of catechin, one of the main components of tea, using SWNTs surface coated with two different biomolecules. Compared to coating with DNA already reported, it can hardly be detected when coated with carboxymethyl cellulose. For nanobiosensing using SWNTs, its sensitivity is not determined only by SWNTs, we found that biomolecules covering the surface are extremely important. In this experiment, we measured the near-infrared absorption spectra of SWNTs coated separately with two different water-soluble polymers; DNA (double-stranded DNA-SWNT complexes) and carboxymethyl cellulose (CMC, CMC-SWNT complexes), and uncovered the differences in their antioxidant properties against the flavonoid catechin. Each dispersion was oxidized with HO at 0.03% (final concentration), following which catechin solutions were added to reduce the samples. Our results showed that the magnitude of the change in the absorbance spectra for dsDNA-SWNT complexes in response to oxidation and reduction was superior to that for CMC-SWNT complexes. The CMC-SWNT complexes exhibited almost no change in their spectra even though the same SWNT powder (produced by the high-pressure carbon monoxide (HiPco) method) was used. On the other hand, when (6, 5)-enriched SWNT powder produced by the ComoCat method was used, no significant change in the absorbance was observed, even though (6, 5)-enriched SWNTs are frequently used for nanobiosensing. Our results revealed that both the SWNT chirality and type of polymer for wrapping SWNTs are important factors for establishing nanobiosensing methods utilizing SWNTs.
我们使用两种不同的生物分子对 SWNTs 表面进行涂层，检测到了儿茶素（茶叶的主要成分之一）的抗氧化活性。与已报道的 DNA 涂层相比，用羧甲基纤维素（CMC）涂层几乎无法检测到。对于使用 SWNTs 的纳米生物传感，其灵敏度不仅取决于 SWNTs，我们发现覆盖表面的生物分子极其重要。在这个实验中，我们分别测量了两种不同水溶性聚合物（DNA（双链 DNA-SWNT 复合物）和羧甲基纤维素（CMC，CMC-SWNT 复合物））涂覆的 SWNTs 的近红外吸收光谱，并揭示了它们对儿茶素的抗氧化性能的差异。将每种分散体分别用 HO 在 0.03％（最终浓度）氧化，然后加入儿茶素溶液以还原样品。结果表明，dsDNA-SWNT 复合物对氧化和还原的吸收光谱变化幅度优于 CMC-SWNT 复合物。即使使用相同的 SWNT 粉末（高压一氧化碳（HiPco）法制备），CMC-SWNT 复合物的光谱也几乎没有变化。另一方面，当使用 ComoCat 方法制备的（6,5）富集 SWNT 粉末时，即使经常用于纳米生物传感的（6,5）富集 SWNTs 也没有观察到吸收的明显变化。我们的结果表明，SWNT 手性和包裹 SWNT 的聚合物类型都是利用 SWNT 建立纳米生物传感方法的重要因素。
