Like-charge attraction and opposite-charge decomplexation between polymers and DNA molecules

Abstract

We scrutinize the effect of polyvalent ions on polymer-DNA interactions. We extend a recently developed test charge theory to the case of a stiff polymer interacting with a DNA molecule in an electrolyte mixture. The theory accounts for one-loop level electrostatic correlation effects such as the ionic cloud deformation around the strongly charged DNA molecule as well as image-charge forces induced by the low DNA permittivity. Our model can reproduce and explain various characteristics of the experimental phase diagrams for polymer solutions. First, the addition of polyvalent cations to the electrolyte solution results in the attraction of the negatively charged polymer by the DNA molecule. The glue of the like-charge attraction is the enhanced shielding of the polymer charges by the dense counterion layer at the DNA surface. Secondly, through the shielding of the DNA-induced electrostatic potential, mono- and polyvalent cations of large concentration both suppress the like-charge attraction. Within the same formalism, we also predict a new opposite-charge repulsion effect between the DNA molecule and a positively charged polymer. In the presence of polyvalent anions such as sulfate or phosphate, their repulsion by the DNA charges leads to the charge screening deficiency of the region around the DNA molecule. This translates into a repulsive force that results in the decomplexation of the polymer from DNA. This opposite-charge repulsion phenomenon can be verified by current experiments and the underlying mechanism can be beneficial to gene therapeutic applications where the control over polymer-DNA interactions is the key factor.

In the present extended version, the derivation of the test charge theory is detailed. A new part on opposite-charge polymer-DNA repulsion is included

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Cited by in corpus (9)

• Controlling Polymer Capture and Translocation by Electrostatic Polymer-Pore Interactions
• Ion correlation driven like-charge attraction in multivalent salt solutions
• Multivalent cation induced attraction of anionic polymers by like-charged pores
• Enhanced polymer capture speed and extended translocation time in pressure-solvation traps
• Theoretical and computational analysis of the electrophoretic polymer mobility inversion induced by charge correlations
• Interaction between two polyelectrolytes in monovalent aqueous salt solutions
• Lateral trapping of DNA inside a voltage gated nanopore
• Mechanisms of electrostatic interactions between two charged dielectric spheres inside a polarizable medium: An effective-dipole analysis
• Understanding long-range opposite charge repulsion in multivalent salt solutions