Viruses possess a rich array of functional nucleic acids and proteins. Genome size limitations and a lifestyle that requires surreptitious entry into cells, followed by rampant replication within them, have endowed viruses with a finely tuned capability to coordinate cellular components and processes. Our use of these features drives fundamental methodology in biotechnology. From exploiting the viral regulatory sequences that enable heterologous gene expression in all kingdoms of life, to the use of viral vectors to protect and deliver replicating nucleic acid therapeutics, virus-derived technologies have become commonplace. With increasing structural knowledge of different viruses comes an opportunity to co-opt nature's nanoscale delivery vehicle for small molecule and protein therapeutics. The research and development of virus-like nanoparticles (VLNPs) exploits the structural characteristics of virus capsids as bionanotechnology platforms with great potential in drug delivery and molecular imaging.