title: An unexpected new optimum in the structure space of DNA solubilizing single-walled carbon nanotubes.
abstract: Here we report quantitative data on the amount of single-walled carbon nanotubes that can be suspended with oligodeoxynucleotides in aqueous buffer, together with rate constants for the thermal denaturation of the resulting DNA-nanotube complexes at elevated temperatures. Sequence motifs d(GT)n and d(AC)n with n=2, 3, 5, 10, 20, or 40 were employed, both individually and as equimolar mixtures of the complementary strands. Unexpectedly, the greatest suspending efficiency was found for the mixture of short, complementary oligonucleotides d(GT)3 and d(AC)3. Unlike the suspending efficiency, the kinetic stability of the nanotube suspensions increases with increasing chain length of the DNA, with half life times of >25 h at 90 degrees C for the complexes of the longest strands. Our results identify a new, unexpected optimum in DNA sequence space for suspending carbon nanotubes. They also demonstrate that suspending power depends on the presence of complementary strands. Exploratory assays suggest that nanotubes can be deposited site-selectively from suspensions formed with short DNA sequences.
authors.affiliation: Institut für Organische Chemie, Universität Karlsruhe TH, 76131 Karlsruhe, Germany.
authors.forename: Stephanie R
authors.initials: SR
authors.lastname: Vogel
authors.forename: Manfred M
authors.initials: MM
authors.lastname: Kappes
authors.forename: Frank
authors.initials: F
authors.lastname: Hennrich
authors.forename: Clemens
authors.initials: C
authors.lastname: Richert
mesh_terms: D004247:DNA / Q000737:chemistry*; D007700:Kinetics; D036103:Nanotechnology; D037742:Nanotubes, Carbon / Q000737:chemistry*; D009691:Nucleic Acid Denaturation; D017422:Sequence Analysis, DNA; D012995:Solubility; D012996:Solutions / Q000737:chemistry; D013057:Spectrum Analysis; D013499:Surface Properties; D013696:Temperature
chemical_list: D037742:Nanotubes, Carbon; D012996:Solutions; D004247:DNA