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Open Access Highly Accessed Research article

pH induced reversible assembly of DNA wrapped carbon nanotubes

Ying Wan1, Gang Liu2*, Xinhua Zhu1* and Yan Su1*

Author Affiliations

1 School of Mechanical Engineering, Nanjing University of Science and Technology, Nanjing, Jiangsu 210094, Peoples Republic China

2 Shanghai Institute of Measurement and Testing Technology, Shanghai 201203, Peoples Republic China

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Chemistry Central Journal 2013, 7:14  doi:10.1186/1752-153X-7-14

Published: 24 January 2013

Abstract

Background

Reversible assembly and disassembly of nanostructures has important function in controllable construction of nanodevices. There are several methods to achieve reversible assembly/disassembly, such as pH, temperature, DNA hybridization and so on. Among these methods, pH driven reversible assembly presents superiority due to its ease-of-use and no waste produced. Herein we report a novel design that use two single-stranded (ss) DNAs wrapped single walled carbon nanotubes (SWCNTs) for the pH controlled assembly of SWCNTs without generation of waste.

Results

Both of the two DNAs with a same wrapping sequence of d(GT)20 and different free terminals showed a very high tendency to wrap around carbon nanotubes. The assembly was driven by the hybridization between the two free terminals of wrapped DNAs on the neighboring SWCNTs: i-motif (four-stranded C-quadruplex) and its complemental stranded G-quadruplex which would form tight tetraplexes and break the hybridization under slightly acidic conditions. Thus the assembly and disassembly are reversibly controlled by pH. And this assembly/disassembly process can be easily distinguished by naked eyes. Gel electrophoresis and Atomic Force Microscope are used to demonstrate the assembly and disassembly of SWCNTs at different pH.

Conclusions

A novel pH induced reversible assembly and disassembly of SWCNTs was realized which may have potential applications in the area of controlled assembly of nanostructures.

Keywords:
pH controlled reversible assembly; Single walled carbon nanotubes (SWCNTs); i-motif; G-quadruplex

Graphical abstract