Chitosan DNA Complex

Fig. 17 Optical images of the DNA-chitosan membrane bound onto rabbit peritoneum. The DNA-chitosan complex membrane showed an adhesive property to rabbit peritoneum tissue...

The transfection mechanism of plasmid-chitosan complexes as well as the relationship between transfection activity and cell uptake was analyzed by using fluorescein isothiocyanate-labeled plasmid and Texas-Red-labeled chitosan. Several factors affect transfection activity and cell uptake, for example the molecular mass of chitosan, stoichiometry of complex, seriun concentration and the pH of the transfection medium. The level of transfection with plasmid-chitosan complexes was found to be highest when the molecular mass of chitosan was 40 or 84 kDa, the ratio of chitosan nitrogen to DNA phosphate was 5, and serum at pH 7.0 was 10%. Plasmid-chitosan complexes most likely condense to form large aggregates (5-8 p,m), which absorb to the cell surface. After this, plasmid-chitosan complexes are endocytosed, and accumulate in the nucleus [97]. 

Hashimoto M, Morimoto M, Saimoto H et al (2006) Lactosylated chitosan for DNA delivery into hepatocytes the effect of lactosylation on the physicochemical properties and intracellular trafficking of pDNA/chitosan complexes. Bioconjug Chem 17(2) 309—316... 

Chitosan is a biodegradable polysaccharide and has been shown to interact with the phosphate groups of DNA, condensing plasmids into spherical and toroidal particles. The colloidal and surface properties of plasmid/chitosan complexes have been shown to depend on the molecular weight of chitosan, the ratio of plasmid to chitosan and the preparation medium. Smaller nanoparticles have been observed with low molecular weight chitosan (2 kDa) as compared to high molecular weight chitosan (540 kDa). A number of cell lines have been transfected with plasmid/chitosan complexes. 

Messai I, Lamalle D, Munier S, et al. (2005). Poly(D,L-lactic acid) and chitosan complexes interactions with plasmid DNA. Colloids and Surfaces A Physicochem. Engin. Aspects. 255 65-72. 

The polyelectrolytic properties of chitosan may further be used to form complexes with DNA plasmid, which are protected from enzymatic degra-dation. 5 MacLaughlin et al. foxmd that plasmid-chitosan complexes with a 1 2 ionic charge ratio were stable in vitro Furthermore, they foxmd that the chitosan complexes, when containing the endosomolytic peptide GM225.1, led to transgene expression in small intestine of rabbits, while naked plasmids yielded no expression. 

Strand, S.P., Danielsen, S., Christensen, B.E. and Varum, K.M. (2005) Influence of chitosan stiucture on the formation and stability of DNA-Chitosan polyelectrolyte complexes. Biomactomolecules, 6, 3357-3366. 

These complexes, known as chitosan/DNA nanosphere, differ from the traditional complexes due to their compact structure and displayed novel properties. The molecular weight and DD of chitosan is the crucial parameter that controls DNA compaction, the nuclease resistance of the complexes, and the dissociation of DNA from chitosan (Koping-Hoggard et al. 2001, Sato et al. 2001). It was reported that the zeta potential, cellular uptake, and cytotoxicity of DNA/chitosan were dependent on DD value of chitosan but independent of the molecular weight of chitosan (Huang et al. 2004). 

Chitosan microspheres act as promising carriers for oral pDNA vaccine in comparison with fish vaccinated with naked pDNA A relative percent survival (RPS) rate of 46% was recorded. Sea bass (Lales calcarifer) orally vaccinated with chitosan-DNA (pVAOMP38) complex showed moderate protection against experimental V. anguillarum infection Squalane oil-containing W/O/W multiple emulsion formulations can significantly enhance the local and systemic immune responses, especially after oral administration... 

Hashimoto, M., Morimoto, M., Saimoto, H. et al. 2006. Gene transfer by DNA/mannosylated chitosan complexes into mouse peritoneal macrophages. Biotechnology Letters 28 815-821. 

There are several steps in gene transfection such as the DNA complexation, cellular uptake of the complexes, release of DNA or complexes from endosomes, release of DNA from the carriers, and transfer into the nucleus (Zabner et al. 1995). Among them, an inefficient release of DNA in the polymer/DNA complexes from endosomes into the cytoplasm is one of the primary causes of poor transfection efficiency as the intracellular barrier. Therefore, pH-sensitive chitosan carriers have been tried to overcome the intracellular barrier. 

Journal of Applied Polymer Science 82, No. 14,27th Dec.2001, p.3391-5 FORMATION OF A DNA/N-DODECYLATED CHITOSAN COMPLEX AND SALT-INDUCED GENE DELIVERY... 

---