Natural polymers gene delivery

Polyethyleneimine Natural Polymer Gene Delivery, Tissue Engineering [13-15]... 

Poly-(3-hydroxybutanoic acid) (PHB), belongs to the large family of poly-(hydroxyalkanoates) (PHAs), high molecular weight natural polymers produced by various microorganisms and stored in cell cytoplasm (200). Low molecular weight PHB, also present in bacteria and are primarily involved in transport of ions and DNA across inner bacterial membrane (201). PHB could be developed as a valuable biocompatible material with possible applications in gene delivery after cytotoxic, safety, and efficacy evaluations. 

A current theme in plasmid-based delivery approaches is to mimic Nature s methods for nucleic acid delivery. To date, the best system to emulate Nature has been viral vectors. Briefly, most viral vectors escape immune surveillance, interact with cell membranes (e. g., receptor), internalize (via endocytosis), escape from endosomes, migrate to the nuclear envelope, enter the nucleus, and finally take over cellular functions. Plasmid-based systems (cationic liposomes and cationic polymers) can mimic portions of these events. This chapter will explore the barriers facing gene delivery vectors, with an emphasis of the pharmacokinetic behavior of these systems. In order to understand the in-vivo barrier, a brief review of physiology will be provided. 

The first reports of using cationic polymers for DNA delivery can be traced back to 1973, before the use of cationic lipids. However, until recently, research in the area of polymer-mediated gene delivery lagged behind that of lipid-based delivery vectors [26]. Recent advances in the development of polymers have regenerated the interest in polymer-mediated gene delivery. Polycationic carriers are either naturally occurring or chemically synthesized compounds. Examples include his-... 

Key Words shRNA RNAi Biodegradable polymer Natural polymer Synthetic polymer Non-viral gene delivery Drug delivery Nanoparticle Microparticle Tumor targeting. 

Though less studied than synthetic polymer and lipid-based gene delivery systems, there have been significant advances in the field of natural polymers for gene delivery. Biodegradable polymers are less likely to accumulate within tissues than their synthetic counterparts. Synthetic polymers are not easily removed by normal clearance systems and can accumulate in tissues. 

Dang, J.M., and Leong, K. W. (2006) Natural polymers for gene delivery and tissue engineering. Advanced Drug Delivery Reviews 58 487-499. 

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