When nanoparticles carrying genetic drugs are injected, the body dictates where they go. We know physical barriers (e.g., blood brain barrier) can alter nanoparticle targeting. There is a lot of evidence that specific genes also affect nanoparticle targeting (and safety). Unfortunately, the genes that affect how well nanoparticles work in vivo are difficult to study, so we don't know what the genes are. What are we doing? We develop tools to study nanoparticle biology directly in vivo. This involves combining molecular biology, chemistry, and in vivo experiments. Why is this important? First, this is super interesting. There may be master regulatory genes that dictate nanoparticle safety. Understanding how to manipulate genes that to improve nanoparticle safety. would help siRNA and Cas9 therapies.