The present invention provides compositions, systems, kits, and methods for expression of one or more biomolecules in a subject, human or non-human mammal, (e.g., at therapeutic levels for the extended periods of time required to produce therapeutic effects). In certain embodiments, compositions, systems, kits, and methods are provided that comprise a first composition comprising polycationic structures (e.g., empty cationic liposomes, cationic micelles, cationic emulsions, or cationic polymers) and a second composition comprising expression vectors (e.g., non-viral expression vectors not associated with liposomes or other carriers) encoding one or more biomolecules of interest.
