Nanotechnology is the study of the fabrication, directed self-assembly, and characterization of materials that have size dimensions between 1 and 100 nanometers. In the context of biological nanostructures, this is the size regime of the molecular machinery that constitutes, for example, functional viruses, bacteria, and human cells. The challenge of bio-nanotechnology and the focus of our lab is to control the synthesis of structures that naturally interface with biological systems to develop exquisitely targeted, practical, safe, and effective nanoparticle therapeutics, imaging agents, and biosensors.