Electrostatic interactions between cationic dendrimers and anionic model biomembrane

The electrostatic interactions between cationic poly(amidoamine) (PAMAM) dendrimers of different generations, G3, G4, and G6, with net anionic model biomembranes have been predicted by adopting an analytical model based on two dissimilar soft spheres. The influence of bilayer surface charge density, ionic strength, pH, temperature, membrane softness (modeled as changes in bilayer thickness), and dendrimer generation on the attractive interaction was investigated. The attraction was found to decrease with increasing salt concentration, dendrimer charge, and thickness (or softness) of the membrane. On the other hand, the attraction increased with the surface charge density of the membrane, and the size of dendrimer generation. In fact, the attraction was found to be much larger for large generations, like G6 dendrimer that have a higher charge, than it is with small ones like G3 and G4 dendrimers. These results have implications for the use of PAMAM dendrimers as potential gene transfection vectors.