Progress of RAFT based polymers in gene delivery

The review provides a comprehensive account on the development of gene delivery vectors via reversible addition-fragmentation chain transfer polymerization (RAFT) approach. Since the development and use of the first non-viral vector for gene delivery applications, a wide range of polymers were synthesized and studied for their gene delivery efficacies. With the advent of living radical polymerization (LRP), well-defined polymers with varying molecular weights, compositions and architectures were synthesized to evaluate their potency as gene delivery vectors. Atom transfer radical polymerization (ATRP) and RAFT are two widely used LRP approaches for gene delivery applications. This review focuses primarily on the synthesis and use of cationic polymers via RAFT for DNA and siRNA delivery in vitro and in vivo. RAFT polymerization has allowed the facile synthesis of tailor-made cationic polymers with pendent biocompatible moieties which are promising non-viral gene delivery vectors. Advanced structure-activity relationship studies between the polymers and gene expression have been possible due to the remarkable control in the design of these polymers via the RAFT process. As a result, biocompatible and non-toxic polymers are produced under aqueous conditions and are identified as potent gene delivery vectors in vitro and in vivo. Polymeric functionalized nanomaterials were produced and studied for gene delivery applications. The consistency of results obtained from different research groups and identification of improved gene expression efficacies of RAFT based gene delivery vectors indicate the scope of this polymerization approach for future studies.