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Preparation of Cationic Comb-Type Copolymer Having Tetra-Alkylammonium Groups and its Interaction with DNA

Author(s): Rui Moriyama, Junji Mochida, Asako Yamayoshi, Naohiko Shimada, Arihiro Kano, Atsushi Maruyama.

Abstract:

The interactions between DNAs and cationic comb-type copolymers like those with quaternary ammonium with N-methylated groups have applications in nanotechnology. N-methylated poly(L-lysine)-graft-dextran copolymers (MPLL-g-Dex) were obtained by methylation of poly(L-lysine)-graft-dextran copolymers (PLL-g-Dex) using dimethyl sulfate under weak basic conditions. The resulting copolymers were characterized using NMR spectroscopy and gel permeation chromatography – multiangle light scattering (GPC-MALS). Both primary and secondary amino groups of the PLL backbones were thoroughly methylated to form quaternary ammonium groups without fragmentation of PLL-g-Dex chains or other detectable side reactions. The interactions of the copolymers with DNAs were assessed by UV melting curves and fluorescence correlation spectroscopic measurements. PLL-g-Dex interacts with double-stranded DNA (dsDNA) in a sequence-independent manner. In contrast the MPLL-g-Dex affinity was lower for dsDNA with higher GC content than for DNA with low GC content. The results suggest that MPLL-g-Dex interacts with DNAs not only through ionic interactions, but also by hydrophobic interactions.

Keywords: DNA, inter polyelectrolyte complex, melting curve, comb-type copolylmer, Tetra-Alkylammonium, hydrophilic graft chains

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Article Details

VOLUME: 7
ISSUE: 6
Year: 2011
Page: [979 - 983]
Pages: 5
DOI: 10.2174/157341311798220600
Price: $58