Interaction between DNA and charged colloids could be hydrophobically driven

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Abstract

The interaction of DNA with amino-functionalized polystyrene particles has been studied by using a dynamic light scattering (DLS) technique. In 10 mM NaBr solution the particles have a hydrodynamic radius of 76 nm and the DNA macromolecule investigated (double stranded) has a hydrodynamic radius of 107 nm. At very low DNA concentrations, DNA adopts a flat conformation on the particle surface. If the DNA concentration is increased above 0.1 mu g/mL, the thickness of the DNA layer increases, suggesting the presence of large loops and tails. Although the particles contain primary amino groups, they have a negative net charge under the conditions used in this work. Thus, the driving force for DNA adsorption is not of electrostatic origin but rather due to a hydrophobic effect. Addition of cationic surfactant to the DNA-precoated amino functionalized particles induces changes in the adsorbed layer conformation, in agreement with the coadsorption of cationic surfactant.

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  • Physical Chemistry
Original languageEnglish
Pages (from-to)832-837
JournalBiomacromolecules
Volume6
Issue number2
Publication statusPublished - 2005
Publication categoryResearch
Peer-reviewedYes