Complexation in Polyelectrolyte Solution with Divalent Surfactant

TL;DR

This study models DNA complexation with divalent cationic surfactants, revealing a cooperative charge neutralization process that occurs at lower concentrations than with monovalent surfactants, implying higher efficiency for transfection.

Contribution

It introduces a simple model showing how divalent surfactants form surfoplexes with DNA through cooperative electrostatic and hydrophobic effects, highlighting their potential for improved transfection.

Findings

Charge neutralization occurs at lower surfactant concentrations with divalent ions.

Divalent surfactants form more efficient complexes than monovalent ones.

Electrostatic and hydrophobic effects drive cooperative binding.

Abstract

We study a simple model of DNA divalent cationic surfactant complexation. We find that the combination of electrostatic and hydrophobic effects leads to a cooperative phenomenon in which as the amphiphile is added to the solution containing DNA, a large fraction of the DNA's charge is neutralized by the condensed divalent cationic surfactants, forming the surfoplex. This binding transition occurs for concentrations that are lower for divalent than for monovalent surfactants. Since the electrostatic strength is larger in the first case and the amount of surfactant lower, we suggest that multivalent amphiphilic molecules would be more efficient than monovalent for transfection.