Formed on the curved nanotube surface, the H-bonded dimer

is of weaker binding energy than the dimer created under usual conditions without surface. Conclusion Hybridization of poly(rC) which is adsorbed to the carbon nanotube surface and free poly(rI) is hampered Selleckchem EPZ015666 because of the strong surface-polymer interaction. Poly(rI) hybridization with poly(rC)NT is characterized with a slow kinetics, the behavior of which differs essentially from hybridization of free polymers. The formation of double-stranded poly(rI)∙poly(rC)NT is confirmed with the appearance of the S-like form of its melting curve representing the temperature dependence of the intensity of UV absorption. But parameters of this dependence differ substantially from those of free poly(rI)∙poly(rC): SBI-0206965 the melting temperature is decreased by 14°C, and the temperature range of helix → coil transition became wider essentially, starting practically from room temperature. In addition to it, the duplex on the nanotube is characterized with a lower hyperchromic coefficient. All these results indicate that the

hybridization of two complementary homopolynucleotides occurs with deviation from the regular structure which is characterized by Watson-Crick pairing of bases. The spectral observation of defective hybridization on the carbon nanotube surface conformed to the results of computer simulation of this process. It was revealed that the strong interaction of nitrogen bases with the nanotube surface before significantly weakens hybridization of two complementary oligomers, as the surface prevents the necessary conformational changes of the polymer to be hybridized. Also, computer simulation showed that before the nitrogen

bases of two strands begin to form dimers (H-bonded or stacked ones), the free oligomer is adsorbed effectively to the nanotube surface, while dimers formed with bases of two strands are unstable and characterized with the hybridization/dissociation process. The modeling results and their following discussion allow us to conclude that, upon the genosensor development employing nanotubes, the direct polymer adsorption onto the nanotube surface should be avoided. Acknowledgements The authors acknowledge the financial supports of this study by NAS of Ukraine Grant 0114U001070; this study was partly supported by State Fund for Fundamental Researches of Ukraine (Grant N 54.1/044). References 1. Wilner OI, Willner I: Functionalized DNA PF-01367338 nanostructures. Chem Rev 2012, 112:2528–2556.CrossRef 2. Boghossian AA, Zhang J, Barone PW, Reuel NF, Kim J-H, Heller DA, Ahn J-H, Hilmer AJ, Rwei A, Arkalgud JR, Zhang CT, Strano MS: Near-infrared fluorescent sensors based on single-walled carbon nanotubes for life sciences applications. Chem Sus Chem 2011, 4:848–863.CrossRef 3. Zheng M, Jagota A, Semke ED, Diner BA, Mclean RS, Lustig SR, Richardson RE, Tassi NG: DNA-assisted dispersion and separation of carbon nanotubes.