The goal of this proposal is to develop sufficient structural and dynamic data on liposome-based and synthetic polymer-based vectors to permit the design of more efficient gene transfer agents. A theoretical model will be derived from the data which includes: Phase diagrams of both carrier types identifying the equilibrium structures as a function of system parameters; Examining possible non-equilibrium structures and the conditions for their formation; and Relating the performance of the various carriers using structure/function relationships. The ultimate goal of this proposal is to identify and quantify the fundamental processes controlling gene transfer via synthetic carriers.