The best of both worlds: DNA-carbon nanotube hybrids

released 11.18.08

Combining molecules from the biological regime with nanotechnological materials offers exciting new possibilities for the design of novel applications, in particular sensory devices, as well as in clinical diagnostics and drug delivery. In particular, DNA has been found to easily connect in a non-covalent fashion to carbon nanotubes (CNTs), thus forming a hybrid system which exhibits many interesting properties that could be utilized in applications. A research collaboration from Michigan Technological University, Uppsala University in Sweden, and the U.S. Army Research Lab has been studying the interaction between DNA and CNTs from first principles, with a special focus on a phenomenon that was observed in several experiments, namely the origin of the dependence of certain key properties on the DNA sequence. In order to solve this puzzle, a better understanding of how individual nucleobases interact with CNTs was first required.

Thanks to computing time at NCSA, the scientists were able to perform a systematic theoretical study to tackle this question, and the results were published in the journal Nanotechnology. The research team discovered that the binding strength of DNA and RNA nucleobases to CNTs is strongly affected by the polarizability of the nucleobase molecule and the diameter of the CNT. This dependence on the polarizability, as well as other findings, led to the conclusion that a van der Waals interaction is the dominant binding force in this system. The team discovered the effect of the diameter of the CNT also plays a role: higher curvature leads to a larger separation of the atoms on the biological molecule and the carbon nanostructure surface and results in a weaker interaction.

Researchers involved in the project were: Shankara Gowtham and Ravindra Pandey, Michigan Technological University; Ralph H Scheicher, Michigan Technological University and Uppsala University, Sweden; Shashi P. Karna, U.S. Army Research Laboratory, and Rajeev Ahuja, Uppsala University and the Royal Institute of Technology, both in Sweden.

Funding was provided by DARPA, the U.S. Army Research Lab, and the Göran Gustafsson and Wenner-Gren foundations.

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