Figure 1.

Schematic illustration of nanoscale ‘polyplexes’ formed by the mixing of aqueous solutions of cationic polymer and negatively charged DNA. The formation of polyplexes is spontaneous and entropically driven, and leads to the formation of colloidal aggregates with dimensions on the order of 100 to 200 nm. Depending on the relative amounts of cationic polymer and DNA used, polyplexes having positive zeta potentials can be formed. Adapted with permission from reference [3].