Gene therapies have reemerged as promising treatments to a number of genetic illnesses. Nearly 400 gene therapy clinical trials are recruiting or ongoing in the United States for diseases such as hemophilia and spinal muscular atrophy (1). The primary vehicles used today to deliver such therapies to patients’ cells are viral vectors such as adenoassociated viruses (AAVs), but producing biologically active vectors for gene therapy can be problematic. One difficulty is generating vectors at the correct concentration to yield a…