Chitosans DNA complexes

Chemical modifications of chitosan assayed to enhance cell specificity and transfection efficiency were reviewed. Also, chemical modifications of chitosan were performed to increase the stabihty of chitosan/DNA complexes [95]. 

Peng SF, Yang MJ, Su CJ et al (2009) Effects of incorporation of poly(y-glutamic acid) in chitosan/DNA complex nanoparticles on cellular uptake and transfection efficiency. Biomaterials 30 1797-1808... 

Kim TH, Kim SI, Akaike T et al (2005) Synergistic effect of poly(cthylcniminc) on the transfection efficiency of galactosylated chitosan/DNA complexes. J Control Release 105(3) 354-366... 

Self-assembled polymeric and oligomeric chitosan/DNA complex is formed by mixing chitosan with plasmid DNA was first reported by Mumper et al. in... 

Ishii et al. [64] explained the transfection mechanism of chitosan/DNA complexes in relation to cell uptake. They used fluorescein isothiocyanate-labeled plasmid DNA and Texas Red-labeled chitosan. They found that the transfection of chitosan/DNA complexes was higher with the molecular weight of chitosan at 40 or 84 kDa and N/P ratio at 5 (Figure 20.4). The transfection... 

The presence of fetal calf serum (FCS) did not affect the transfection efficiency of the chitoplexes, whereas the transfection efficiency of DOTAP-DNA complexes was decreased. Cells remained 100% viable in the presence of chitosan oligomers whereas viability of DOTAP treated cells decreased to 50% in both cell lines. Both DOTAP-DNA lipoplexes and chitoplexes resulted in less transfection efficiency in Caco-2 cell cultures than in COS-1 cells however, quaternized chitosan oligomers proved to be superior to DOTAP. The effects on the viability of Caco-2 cells were similar to the effects observed in COS-1 cells. This report is also in line with the earlier one suggesting that chitosan-DNA complexes present suitable characteristics and less cytotoxic compared to lipid gene carriers and thus has the potential to be used as gene delivery vectors. 

Lee, J. M., Ha, K. S., and Yoo, H. S. 2008. Quantum-dot-assisted fluorescence resonance energy transfer approach for intracehular trafficking of chitosan/DNA complex. Acta Biomaterialia 4 791-798. 

The primary amines of chitosan become positively charged below pH 5.5 because the pK value of the chitosan is around 6.3-6.4 (Li et al. 1996). Therefore, it can be expected that the transfection efficiency of the chitosan/DNA complexes will be largely affected by the pH of the culture medium. Several researchers reported that the highest expression efficiency was obtained between pH 6.5 and pH 7.0 and the transfection efficiency rapidly decreased above pH 7.2 due to the dissociation of DNA from the chitosan/DNA complexes above pH 7.2 (Zhao et al. 2006). 

Chitosan/DNA complexes have been reported to transfect various cell types such as HeLa, HEK293, A549, Caco-2, HT-1080, M69 mesenchymal cells, MG63, and COS-1 cells (Kiang et al. 2004). 

Among the used cells, HEK293 cells were more efficiently transfected than other cells with chitosan/DNA complexes (Leong et al. 1998), although its exact mechanism is not clear. 

Parameters Affecting Transfection Efficiency of Chitosan/DNA Complexes or Gene Silencing of Chitosan/siRNA Complexes... 

Optimum conditions for transfection efficiency of chitosan/DNA complexes or gene silencing of chitosan/siKNA complexes should be clarified for clinical trials. A schematic illustration of the parameters affecting transfection efficiency of chitosan/DNA complexes has already been reported by Kim et al. [12],... 

---