In order to compact DNA, linear cations are believed to bind in DNA grooves and to interact with the phosphate backbone of apposing helices. The DeRouchey group has previously shown a length dependent attraction resulting in higher packaging densities with increasing charge for linear cations. Hyperbranched polycations, such as polycationic dendrimers, presumably would not be able to bind to DNA and correlate their charges with the phosphates of adjoining DNA in the same manner as linear cations. We use osmotic stress coupled with x-ray scattering to study fundamental molecular scale interactions and supramolecular self-assembly of low generation poly(amido amine) (PAMAM) dendrimer-DNA complexes. Dendrimer-DNA assembly displays fundamentally different physical behavior; higher dendrimer generation number give lower DNA packaging densities. The salt and pH dependence of packaging in dendrimer-DNA complexes was also measured. These studies begin to elucidate the role of cation topography in DNA condensation.

Intermolecular forces in DNA condensation with cationic dendrimers

245th National Meeting (2013)

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