Adsorption of DNA onto positively charged amidine colloidal spheres and the resultant bridging interaction

Hodrien, A. J. and Waigh, T. A. and Voice, A. M. and Blair, G. E. and Clarke, S. M. (2007) Adsorption of DNA onto positively charged amidine colloidal spheres and the resultant bridging interaction. International Journal of Biological Macromolecules, 41 (2). pp. 146-153. DOI


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The complexation behaviour of duplex linear DNA (negatively charged) with amidine functionalised sub-micron latex spheres (positively charged) was studied using dynamic light scattering (DLS) and a PALS interferrometric zeta potential sizer. Four types of DNA-sphere complex were investigated as a function of component concentration by combining amidine functionalised polystyrene microspheres with radii of 10.5 nm and 60 nm, and herring DNA of lengths of 35 nm and 85 nm. At low DNA concentrations (cDNA), the undercharged complexes showed a small increase in measured hydrodynamic radius (Rh) and a decrease in zeta potential with increasing cDNA. Within a critical DNA concentration range Rh was seen to peak sharply, and the zeta potentials were 0 mV, corresponding to the formation of unstable neutral complexes. Immediately above this concentration region the measured Rh values became comparable with those at low cDNA, and the zeta potential became negative, indicating the formation of stable overcharged complexes. The small and large spheres formed multi-sphere and single sphere overcharged aggregates respectively, which is thought to be determined by the relative magnitude of the chain persistence length (50 nm) and the sphere radius, switching on or off the DNA bridging interaction.

Item Type: Article
Uncontrolled Keywords: BPI IA49
Subjects: 99 - Other
Divisions: 99 - Other
Journal or Publication Title: International Journal of Biological Macromolecules
Volume: 41
Page Range: pp. 146-153
Identification Number:
Depositing User: Sarah Humbert
Date Deposited: 16 Feb 2009 13:02
Last Modified: 23 Jul 2013 10:07

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