Zhao Chao, Song Yujun, Ren Jinsong, Qu Xiaogang
Changchun Institute of Applied Chemistry, Graduate School of the Chinese Academy of Sciences, Jilin, China.
Biomaterials. 2009 Mar;30(9):1739-45. doi: 10.1016/j.biomaterials.2008.12.034. Epub 2009 Jan 4.
Single-walled carbon nanotubes (SWNTs) can selectively induce human telomeric i-motif DNA formation at pH 7.0. Based on this property, we design a DNA nanomachine induced by SWNTs on gold surface. The motor DNA is human telomeric G-quadruplex DNA. The reversible hybridization between the motor DNA and its complementary human telomeric i-motif DNA can be modulated by SWNTs without changing solution pH. Up to now, to our knowledge, there is no report to show that a DNA nanomachine is induced by SWNTs or a DNA nanomachine can detect i-motif formation at pH 7.0. Our work may provide a new concept for designing an SWNT-induced DNA nanomachine and for the detection of i-motif DNA structure at pH 7.0. DNA hybridization, conformational transition and i-motif formation have been characterized on surface or in solution by fluorescence confocal microscopy, circular dichroism, DNA melting and gel electrophoresis. The folding and unfolding kinetics of the DNA nanomachine on gold surface were studied by Fourier transform-surface plasmon resonance (FT-SPR). All these results indicate that SWNTs can induce the DNA nanomachine to work efficiently and reversibly. Therefore our work will provide new insights into the design and application of SWNT-induced DNA nanodevice under physiological conditions.
单壁碳纳米管（SWNTs）在pH 7.0时可选择性诱导人端粒i-基序DNA形成。基于这一特性，我们设计了一种在金表面由SWNTs诱导的DNA纳米机器。驱动DNA为人端粒G-四链体DNA。驱动DNA与其互补的人端粒i-基序DNA之间的可逆杂交可由SWNTs调控，而无需改变溶液pH。据我们所知，到目前为止，尚无报道表明DNA纳米机器可由SWNTs诱导或DNA纳米机器能在pH 7.0时检测i-基序形成。我们的工作可能为设计SWNT诱导的DNA纳米机器以及在pH 7.0时检测i-基序DNA结构提供一个新概念。通过荧光共聚焦显微镜、圆二色性、DNA熔解和凝胶电泳等方法，对表面或溶液中的DNA杂交、构象转变和i-基序形成进行了表征。利用傅里叶变换表面等离子体共振（FT-SPR）研究了金表面DNA纳米机器的折叠和解折叠动力学。所有这些结果表明，SWNTs可诱导DNA纳米机器高效、可逆地工作。因此，我们的工作将为生理条件下SWNT诱导的DNA纳米器件的设计和应用提供新的见解。
