Polymer-based gene delivery system fabricated with the participation of a polyanion

A polymer-based gene delivery system, denoted as “DNA/polycation/polyanion”, is designed based on the concept of polyelectrolyte multilayer fabrication by the layer-by-layer polyelectrolyte self-assembly technology. The comparisons of the physicochemical properties between ‘core’ DNA/branched polyethylenimine (PEI) and DNA/chitosan complexes suggest that DNA/PEI complexes form as colloidally stable, well-dispersed, homogeneous and small around 100 nm (at pH 7.4) or 70 nm (at pH 4.0). When depositing the polyanion layer around the ’core’, hyaluronic acid (HA) is found not to dissociate DNA/PEI complexes. DNA/PEI/HA complexes with increased size around 200~300 nm have thus been produced as the designed gene delivery system.