Preparation of Novel Core-shell Nanoparticles as Non-viral Gene Delivery Vectors: Surface Charge, Particle size, and Morphology

The well-defined core-shell amphiphilic nanoparticles consisting of the poly(methyl methacrylate) (PMMA) cores surrounded by the modified chitosan shells were prepared via a surfactant-free emulsion graft-copolymerization of methyl methacrylate from an aqueous modified chitosan solution induced by a small amount of tert-butyl hydroperoxide. The PMMA-chitosan core-shell particles have an average particle diameter of approximately 200 nm and display highly positive surface charges (+70 mV). Transmission electron microscopic (TEM) images clearly reveal a well-defined core-shell morphology of the nanoparticles where the PMMA cores are coated with chitosan shells. The core-shell nanoparticles were investigated as novel carriers for gene delivery. The nanoparticle/plasmid DNA complexes were characterized with respect to their binding affinity, particle size, and zeta-potential.