Heller Daniel A, Jeng Esther S, Yeung Tsun-Kwan, Martinez Brittany M, Moll Anthonie E, Gastala Joseph B, Strano Michael S
Department of Chemistry, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA.
Science. 2006 Jan 27;311(5760):508-11. doi: 10.1126/science.1120792.
The transition of DNA secondary structure from an analogous B to Z conformation modulates the dielectric environment of the single-walled carbon nanotube (SWNT) around which it is adsorbed. The SWNT band-gap fluorescence undergoes a red shift when an encapsulating 30-nucleotide oligomer is exposed to counter ions that screen the charged backbone. The transition is thermodynamically identical for DNA on and off the nanotube, except that the propagation length of the former is shorter by five-sixths. The magnitude of the energy shift is described by using an effective medium model and the DNA geometry on the nanotube sidewall. We demonstrate the detection of the B-Z change in whole blood, tissue, and from within living mammalian cells.
DNA二级结构从类似B构象到Z构象的转变会调节其吸附的单壁碳纳米管（SWNT）周围的介电环境。当一个30个核苷酸的包封寡聚物暴露于屏蔽带电主链的抗衡离子时，SWNT带隙荧光会发生红移。DNA在纳米管上和纳米管外发生的这种转变在热力学上是相同的，只是前者的传播长度短六分之五。通过使用有效介质模型和纳米管侧壁上的DNA几何结构来描述能量转移的幅度。我们展示了在全血、组织以及活的哺乳动物细胞内对B-Z变化的检测。
