Gene delivery Subject

Gene delivery vehicles can be divided into essentially one of two categories recombinant viruses and synthetic vectors. The majority of synthetic vectors, furthermore, can be divided into polymers (the subject of this review) and liposomes. Each type of material has important advantages and disadvantages. In order to best understand the problems facing polymer-based gene delivery vehicles and their current state of development, it is useful to briefly examine the alternate methodologies (Table 1). 

The subject of this review is complexes of DNA with synthetic cationic polymers and their application in gene delivery [1 ]. Linear, graft, and comb polymers (flexible, i.e., non-conjugated polymers) are its focus. This review is not meant to be exhaustive but to give representative examples of the various types (chemical structure, architecture, etc.) of synthetic cationic polymers or polyampholytes that can be used to complex DNA. Other interesting synthetic architectures such dendrimers [5-7], dendritic structures/polymers [8, 9], and hyperbranched polymers [10-12] will not be addressed because there are numerous recent valuable reports about their complexes with DNA. Natural or partially synthetic polymers such as polysaccharides (chitosan [13], dextran [14,15], etc.) and peptides [16, 17] for DNA complexation or delivery will not be mentioned. 

The Klymchenko group introduced a hierarchical assembly protocol between amphiphilic calixarenes such as 71 and DNA to generate virus-sized nanoparticles for gene delivery (Fig. 24.24). In a two-step process cationic calix[4]arenes with choline headgroups at the upper and long alkyl tails at the lower rim were subjected... 

Kleimnan et al. 2008). In addition, synthetic siRNAs are also subject to degradation in vivo by nuclease activity. Besides side effects and instability, the efficient and specific delivery of the RNAi indncers to the target cell still requires optimization. Here we snmmarize the cnrrent statns of nncleic acid-based antiviral therapentics. The focns will be on antiviral strategies nsing antisense and RNAi technology. Additionally, antiviral ribozymes and aptamers will be discussed briefly, with a focus on recent studies. Gene therapy approaches and delivery systems are the subject of Chapter 11 of this book. 

The major expansion in this present volume concerns the subjects of proteomics and gene therapy, both of which offer so much promise for the future. Pulmonary administration is another likely route of delivery for the future and this is reviewed separately. Conventional wisdom suggests that proteins cannot be delivered orally but there is strong evidence suggesting that this is not always true and this is another exciting area that is reviewed here. The earlier review of vaccines has been expanded considerably since this is another area of current interest with potential for wider future application. 

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