Coupling carbon nanotubes through DNA linker using a biological recognition complex

We present a simple and versatile method for linking single wall carbon nanotubes (SWNT) together through DNA by non-covalent chemistry using streptavidin-biotin recognition complex. Streptavidin coated SWNTs are reacted with biotin or bis-biotin ended DNA double strands leading to SWNT-DNA and SWNT-DNA-SWNT adducts in high yield. This method avoids strong acidic treatment of SWNTs prior to functionalization as usually required in covalent routes. Complementary characterizations by gel electrophoresis and AFM demonstrated the efficiency of the present binding method. In addition, SWNTs bound to DNA can be aligned on a substrate using the combing properties of DNA strands, bringing a new tool into the toolkit for self-assembling SWNTs onto surfaces. (c) 2006 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.