CHAPTER 3: Well-Defined Cationic Polymers for Nucleic Acid Delivery Check Access

A large number of cationic polymers has been prepared and studied for their gene delivery efficacies, since the failure of retro-virus vector-based gene therapy trials in the 2000s. The introduction of the living radical polymerization (LRP) approach has allowed the synthesis of tailored gene delivery vectors of known molecular weights, architectures and compositions for gene delivery applications. The term “gene delivery” refers to the delivery of both deoxyribonucleic acid (DNA) and small interfering ribonucleic acid (siRNA) in living cells and tissues. Although the cargo delivery site for the two nucleic acids is different, the basic components of cationic vectors exploited in the design of gene delivery vectors are essentially the same. For LRP, atom transfer radical polymerization (ATRP) and reversible addition–fragmentation chain transfer polymerization (RAFT) have allowed the synthesis of cationic vectors of near precise dimensions, hence establishing structure–activity relationships between cationic vectors and their gene delivery profiles. This attribute of LRP has enabled researchers to pinpoint and overcome the hurdles associated with traditional cationic polymers for gene delivery applications. In this chapter a brief account of the types of cationic vectors prepared by LRP and their role in gene expression in vitro and in vivo is discussed.