| Gene therapy offers an alternative therapeutic approach for a variety of diseases and genetic disorders that conventional therapies currently manage. In order to clinically advance this therapeutic alternative, more safe and efficient gene delivery vehicles must be continuously developed. To date, the development of safe and efficient gene delivery reagents for clinical application is hampered by undefined design and formulation requirements. In an attempt to further elucidate these requirements for improved gene delivery reagents, research labs often engineer and study many putative products that possess subtle physiochemical differences that may influence carrier function and biological activity. The synthesis of many putative gene delivery reagents, however, requires multiple optimization cycles for each product, is time-intensive, laborious and costly.;As such, the intent of this dissertation is to implement a method that facilitates evaluation ease of novel, modified gene delivery reagents by avoiding the synthesis of many putative products for the identification of optimal candidates and reagent properties. This method uses mixtures of a promising nonviral gene delivery reagent and its modified counterpart, whereby the relative amount of each species in the formulation mixture is easily controlled, and thus, physiochemical differences and their influence on biological activity can be studied to identify optimal reagent candidates.;The initial part of this dissertation focuses on the chemical modification of a previously published and flourishing non-viral, polycationic gene delivery vehicle, poly(triethylenetetramine/cystamine bisacrylamide) (p(TETA/CBA)) with poly(ethylene glycol) (PEG) to derive poly(triethylenetetramine/cystamine bisacrylamide)-g-poly(ethylene glycol) (p(TETA/CBA)-g-PEG) with physiochemical properties different form p(TETA/CBA) alone. Subsequent studies focused on improving the synthetic ease of p(TETA/CBA)-g-PEG as well as improving its tissue specificity for oncogenic cells and their associated vasculature via modification using a tumor specific peptide. As a result, design and formulation requirements for safe and efficient gene delivery carriers is further clarified and several new and promising gene delivery reagents are born. |
