In the past few years gene delivery system has gained a huge attention owing to its proved efficacy in several diseases especially in those caused by genetic and/oroncological malfunctioning. The effective gene delivery mainly depends on the carrier molecules that can ensure the safe and specific delivery of the nucleic acidmolecules. Viral vectors have been used for a longer period as the gene transfer vehicle. However, these viral vectors have potential immunological disadvantages that made them less preferred. Recently, non-viral vectors such as polyplexes have emerged as a promising alternative for viral vectors. Polyplexes are formed by conjugating a polymer with DNA and in maximum cases the cationic polymers are preferred over others. The structure and stability of the polyplexes depends on various factors. The ability of the polymer to condense the DNA mainly dictates the efficiency of the polyplex mediated transfection. In this review we are going to provide a framework for the synthesis and design of the polyplexes along with the structure and stability of the complexes pertaining to mechanism of action, characterization and therapeutic application, including polyethyleneimine mediated cytotoxicity as well as newer strategies for the generation of better polyplexes.
485. Biodegradable Polymer-Based Gene Delivery System for Repeat Administration
