Divalent Ion and Thermally Induced DNA Conformational Polymorphism on Single-walled Carbon Nanotubes
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- 作者：Hong Jin ; Esther S. Jeng ; Daniel A. Heller ; Prakrit V. Jena ; Robert Kirmse ; Jö ; rg Langowski ; Michael S. Strano
- 刊名：Macromolecules
- 出版年：2007
- 出版时间：September 4, 2007
- 年：2007
- 卷：40
- 期：18
- 页码：6731 - 6739
- 全文大小：764K
- 年卷期：v.40,no.18(September 4, 2007)
- ISSN：1520-5835
文摘
Various sequences of single and double stranded DNA can wrap and colloidally stabilize single-walled carbon nanotubes in solution. The binding of divalent ions to these complexes results in a 10 meV emissionenergy red-shift of the photoluminescence of the nanotube. In this work, this optical modulation is linked tospecific secondary structure changes in the adsorbed DNA. Dynamic light scattering is used to rule out aggregationand inter-particle effects. It is observed that the transition can also be induced thermally over the temperaturerange between 0 and 50 
C without ion addition. Interestingly, we find evidence of the dissociation of a DNAduplex at the surface, as confirmed using both selective dialysis and DNA electrophoresis on a 20% PAGE gel.Consistent with several observations is a mechanism that proceeds via a competitive, stepwise process of partialdesorption of the DNA along the length of SWNT. A two-state mathematical model quantitatively describes theequilibrium for various divalent ions binding to DNA adsorbed at the nanotube surface.
C without ion addition. Interestingly, we find evidence of the dissociation of a DNAduplex at the surface, as confirmed using both selective dialysis and DNA electrophoresis on a 20% PAGE gel.Consistent with several observations is a mechanism that proceeds via a competitive, stepwise process of partialdesorption of the DNA along the length of SWNT. A two-state mathematical model quantitatively describes theequilibrium for various divalent ions binding to DNA adsorbed at the nanotube surface.