DNA Directed Self-Assembly of Carbon Nanotube Structures

Citation

Han, Si-ping (2011) DNA Directed Self-Assembly of Carbon Nanotube Structures. Dissertation (Ph.D.), California Institute of Technology. doi:10.7907/3ZN9-T618. https://resolver.caltech.edu/CaltechTHESIS:12162010-142822030

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Abstract

Production of pure carbon nanotube species and organization of nanoscale structure are two fundamental barriers to the utilization of CNTs in nanoelectronics. We have developed new methods to characterize double walled carbon nanotube (DWNT) structure by Raman spectroscopy and organize single walled carbon nanotube (SWNT) constructs using DNA.

First, using atomistic force fields calculations, we have shown that the radial breathing modes (RBM) of double walled carbon nanotubes can be accurately modeled as two uniform concentric cylindrical elastic shells coupled by a van der Waals interaction. This model leads to a simple equation which can be solved to give accurate RBMs (given diameters) or diameters (given RBMs).

Secondly, we have developed a method for using DNA origami to template the assembly of complex SWNT structures. In this process, SWNTs are modified with non-covalently attached DNA linkers that present duplex labeling domains for base pairing to complementary single stranded hooks on customized DNA origami. We show that the SWNTs attach at positions and in orientations specified by their labeling sequence, and that nanotube cross-junctions assembled from two different SWNTs in this manner can behave as field effect transistors.

Finally, we have devised a method for using DNA linkers to organize arrays of parallel SWNTs with uniform and selectable inter-nanotube separation of <20 nm. SWNTs are first dispersed in aqueous solution with DNA linkers-spacers that non-covalently anchor onto their sidewalls. When the modified SWNTs are then deposited on mica or polar lipid bilayers and allowed to diffuse on the surface, they form parallel arrays of SWNTs in which different domains of the DNA linker-spacers act to maintain array cohesion and enforce uniform separation. Thus, the use of 7 bp, 20 bp, and 60 bp DNA spacer domains result in ~3 nm, ~8.5 nm, and ~22 nm inter-nanotube separations. We further use the spacer domains as rigid scaffolds for the positioning of Streptavidin proteins between adjacent nanotubes, and give a simple method for transfer of intact arrays onto adhesive glass substrates. Further development of this technology could lead to wafer scale organization of dense parallel SWNT decorated with heterogeneous nanoscale objects.

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