The use of polymer nanoparticles to deliver therapeutic nucleic acids and drugs in gene/cancer therapy applications is limited because their delivery mechanisms are poorly understood.  Local interactions between these nanoparticles and their local biological environment dictate the efficiency of how polymer delivery vehicles enter cells, escape degradation in lysosomes, and successfully deliver their cargo.  The goal of this project is to visualize these interactions to directly establish how polymer delivery vehicle structures influence their biological activities and intracellular cargo delivery functions.  This work will help guide the rational development of more effective delivery vectors.