Chitosan micro-and nanospheres: Fabrication and applications for drug and dna delivery

Polysaccharides and other cationic polymers have been recently used in pharmaceutical research and industry for their properties to control the release of antibiotics, DNA, proteins, peptide drugs or vaccines and have been also extensively studied as non viral DNA carriers for gene delivery and therapy. Among them, chitosan is the most used since it can promote long term release of incorporated drugs. Here, we reviewed several works aimed to prepare chitosan micro- and nanospheres using different manufacturing processes (nanofabrication). Moreover, we recently reported that the preparation of chitosan and chitosan/DNA nanospheres by using a novel and simple osmosis-based method, recently patented may be an useful alternative to obtain nanospheres for biomedical application. The morphology of chitosan/DNA particles is spherical (SEM) and the nanospheres average diameter is 38 4 nm (DLS). With this method, DNA is incorporated with high yield (up to 30%) and the release process is gradual and prolonged in time. The reported method has general applicability to various synthetic or natural biopolymers. Solvent, temperature and membrane cut-off are the physicochemical parameters able to control the overall osmotic process leading to obtain several nanostructured systems with different size and shape that may be used in several biotechnological applications.