The objective of the proposed research is to develop the knowledge and techniques to generate polymeric materials specifically designed to deliver genetic material to human cells. These materials can be termed "artificial viruses" and could bring benefits such as: (a) the capacity to carry large genes, (b) improved safety, (c) systematic administration, and (d) relatively easy production and purification. This research will focus on understanding how DNA/polymer complexes (polyplexes) navigate through the cell. To deliver DNA from outside the cell to the nucleus, a vector must be endocytosed, escape from endocytic vesicles, undergo transport to and across the nuclear envelope, and release the DNA from the complex. The proposed research will focus on escape from the endocyric vesicles and transport to the nuclear envelope, since these are often thought to be the limiting steps. The research will also address the role of the cytoplasmic motility of polyplexes in moving through the cytosol to the nuclear membrane. The speck aims of this research are to: (1) to quantify the effects of polymer buffering on escape from the endocytic vesicles, (2) elucidate the mechanism of polyplex transport across the nuclear membrane, and (3) determine the kinetics and mechanisms of transport of polyplex vectors through the cytoplasm.