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Issue 20, 2012
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Structure and stability of the complex formed by oligonucleotides

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Polycations and cationic lipids have been widely used as non-viral vectors for the delivery of plasmid DNA, siRNA and anti-sense oligonucleotides. To demonstrate that one polycation can form a complex with several types of DNA, we conducted a comparative study on the complexation of poly(L-lysine) (PLL) with 2000 bp salmon testes DNA (dsDNA), 21 bp double-stranded oligonucleotides (ds-oligo), and 21 nt single-stranded oligonucleotides (ss-oligo) in PBS buffer. The complexes are prepared by a titration method and the process is monitored by laser light scattering. It was found that in most cases, ss-oligo and ds-oligo form complexes with higher molecular weights than the complex formed by dsDNA at the same +/− ratio immediately after mixing. More importantly, the complexes formed by oligonucleotides are not stable, the scattered intensity gradually decreases to the level of the solvent in weeks. Atomic force microscopy measurements also indicate that the freshly prepared complex is subject to environmental changes and could dissociate very quickly. The behaviour of oligonucleotides cannot be predicted by the classical polyelectrolyte theories.

Graphical abstract: Structure and stability of the complex formed by oligonucleotides

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The article was received on 22 Dec 2011, accepted on 28 Mar 2012 and first published on 28 Mar 2012

Article type: Paper
DOI: 10.1039/C2CP24086F
Citation: Phys. Chem. Chem. Phys., 2012,14, 7352-7359
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    Structure and stability of the complex formed by oligonucleotides

    C. Zheng, L. Niu, J. Yan, J. Liu, Y. Luo and D. Liang, Phys. Chem. Chem. Phys., 2012, 14, 7352
    DOI: 10.1039/C2CP24086F

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