Natural cationic polymers gene delivery

Natural Cationic Polymers for Advanced Gene and Drug Delivery... 

Although chitosan is the most important and well-studied natural cationic polymer, other natural cationic polymers have also been investigated for their applieations in gene and drug delivery. Different from ehitosan, these polymers are eationic modified natural polymers or cationic peptides, sueh as eationie eellulose, cationie dextrin or starch, cationic gelation, and others. 

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-... 

Cationic lipids and cationic polymers are designed as gene delivery systems on the nanoscale. Especially chitosan is under focus as a biodegradable, natural biopolymer, used both as the polyplex and also as a coating material for other polyplexes. Chitosan-coated poly(isohexyl cyanoacrylate) nanoparticles have also been developed for intravenous delivery of siRNA and no evidence of toxicity was observed after intravenous administration for 30... 

Cationic polymers are of particular interest carriers in drug and gene deliveiy because of their ability to promote cellular uptake.This holds also for the delivery of proteins, especially for those that possess an overall anionic charge at pH values above the isoelectric point (p/). These proteins can form soluble, nanosized, polyelectrolyte complexes with natural or synthetic cationic polymers by simply mixing the oppositely charged protein and polymer that self-assemble by electrostatic attraction, as represented in Scheme 14.1. 

Chitosan and cyclodextrins are mainly used as natural polymers for gene delivery to the brain. In 2007, Thakor et al. used cationized gelatin to... 

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