A novel method to obtain chitosan/DNA nanospheres and a study of their releaseproperties

Abstract

Polysaccharides and other cationic polymers have recently been used in pharmaceuticalresearch and industry for their properties to control the release of antibiotics, DNA, proteins,peptide drugs or vaccines, and they have also been extensively studied as non-viral DNAcarriers for gene delivery and therapy. Among them, chitosan is the most used since it canpromote long-term release of incorporated drugs. This work is focused on the preparationof chitosan and chitosan/DNA nanospheres by using a novel and simple osmosis-basedmethod, recently patented. The morphology of chitosan/DNA particles is spherical (asobserved by scanning electron microscopy, SEM) and the nanospheres’ average diameter is38 ± 4 nm (obtained by dynamic light scattering, DLS). With this method, DNA is incorporatedwith high yield (up to 30%) and the release process is gradual and prolonged in time.The novelty of the reported method resides in the general applicability to varioussynthetic or natural biopolymers. Solvent, temperature and membrane cut-off are thephysicochemical parameters that one is able to use to control the overall osmotic process,leading to several nanostructured systems with different size and shape that may be used inseveral biotechnological applications.