Gene delivery system cationic polymers

Polymer. The field of nonviral gene delivery using cationic polymers is at its early stage compared to that of cationic lipid. However, this system is also known to have advantages over lipid-based systems in controlling the size, charge, and other physicochemical properties. Polycation-DNA complexes, also called as polyplexes, are formed by a cooperative... 

Garnett, M. C. 1999. Gene-delivery systems using cationic polymers. Crit Rev Ther Drug Carrier Syst 16(2) 147-207. 

Nonviral vector systems are usually either composed of a plasmid based expression cassette alone ( naked DNA), or are prepared with a synthetic amphipathic DNA-complexing agent (84, 88). Gene delivery systems based on nonviral vectors mainly comprise cationic liposomes, DNA-polymer-protein complexes, and mechanic administration of naked DNA. An idealized/optimized multifunctional nonviral gene delivery system is depicted in Figure 13.4. 

Several major barriers need to be overcome for the development of nonviral gene delivery systems into true therapeutic products for use in humans. These barriers fall into three classes manufacturing, formulation, and stability (extracellular barriers and intracellular barriers) (85). Cationic lipids and cationic polymers self-assemble with DNA to form small particles that are suitable for cellular uptake. At the therapeutic doses positively charged particles readily aggregate as their concentration increases, and are quickly precipitated above their critical flocculation concentration. 

Cationic Polymer-Based Gene Delivery Systems... 

De Smedt, S.C., Demeester, J. and Hennink, W.E. (2000) Cationic polymer based gene delivery systems. Pharm. Res., 17, 113-126. 

Cationic synthetic polymers such as PEI, PEL and PMA are widely studied for drug and gene delivery systems. ... 

Cationic lipids and cationic polymers are designed as gene delivery systems on the nanoscale. Especially chitosan is under focus as a biodegradable, natural biopolymer, used both as the polyplex and also as a coating material for other polyplexes. Chitosan-coated poly(isohexyl cyanoacrylate) nanoparticles have also been developed for intravenous delivery of siRNA and no evidence of toxicity was observed after intravenous administration for 30... 

There have been a number of strategies to reduce the cytotoxicity of cationic polymers for their use in various drug and gene delivery systems (Table 18.2). 

Cationic Polymer-Based Non-viral Gene Delivery Systems and their Application in Gene-Engineered Stem Cells... 

---