Gene delivery system advantages

Although viral-mediated gene delivery systems currently predominate, a substantial number of current clinical trials use non-viral-based methods of gene delivery. General advantages quoted with respect to non-viral delivery systems include ... 

The gene delivery systems presented in this section represent those with the most information regarding characterization and application. Each system has advantages and disadvantages. For this reason, there may be a disease application for one type of system that is not suitable for another. A few years ago, gene therapy was criticized for the number of clinical trials that had been completed with little or no success. Only in the past few years have demonstrations of benefit been realized to validate the concept. The question is no longer will this form of therapy be employed to treat disease, but when it will be employed. 

The necessity of more efficient gene delivery methods prompted the search for novel, less charged or non-cationic gene delivery systems. These non-electrostatic complexes can be advantageous for in vitro and in vivo applications, since unlike cationic lipid/DNA complexes, the novel molecules could not lead to a compacted state of DNA, and could therefore potentially lead to different kinetics of DNA release from complexes. Several compounds are able to bind to double stranded DNA along the grooves by the formation... 

Several amine functionalized hyperbranched PGs have been reported as potential gene delivery systems after a proper surface group functionalization. In comparison to other dendritic structures, these scaffolds have the added advantage of being open, flexible, and possessing a polyether backbone which keeps the toxicity profile low. Different systems have been studied by post-modification of the hydroxyl groups... 

Overall, the major advantages seen in using USCAs as a gene delivery system are ... 

Of the many nonlipidic polycation gene delivery systems developed in the past decades, poly(L-lysine) (PLL) was the hrst polycation used for nonviral gene delivery [34]. Among a vast number of other positively charged polymers, polyethyleni-mine (PEI) has been widely used for nonviral transfection in vitro and in vivo and has an advantage over other polycations in that it combines strong DNA condensation capacity with an intrinsic endosomolytic activity [35-38]. 

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