Effects of hydrophobicity in DNA surfactant complexation

We study a simple model of DNA cationic surfactant complexation. It is found that a combination of electrostatic and hydrophobic effects leads to a cooperative binding transition in which a large fraction of the DNAʹs charge is neutralized by the condensed cationic surfactants. A further increase of surfactant density can result in charge inversion of the DNA–surfactant complexes. This regime should be of particular interest for application to gene therapy. In this paper we shall explore the dependence of the cooperative binding on hydrophobic interactions between the DNA and amphiphilic molecules.