Cationic polymers for the delivery of therapeutic nucleotides

Gene therapy is a promising approach for treatment or prevention of wide range of diseases associated with defective gene expression. It involves the insertion of a therapeutic gene into cells, followed by expression and production of the required proteins. Two main delivery systems, including viral or non-viral gene carriers, are currently deployed for gene therapy. Although viruses are currently the most commonly researched vector, however, the need to resolve drawbacks related to viral vectors (e.g., high risk of mutagenicity, immunogenicity, low production yield, limited gene size) led to the development of non-viral vectors. Several non-viral modalities are reported to transfer foreign genetic material into cells; cationic polymers constitute one of the most promising approach. For this reason, various cationic polymers with diminished cytotoxicity and enhanced efficacy are rapidly emerging as systems of choice. This chapter provides an overview and recent developments of cationic polymers employed for in vitro and in vivo delivery of therapeutically important nucleotides, e.g., DNA and siRNA. The mechanism and recent progress in cationic polymer based gene delivery are reviewed in detail.