At those sizes, 3D containers are too tiny to be assembled by a machine. They have to come together on their own. Seem like science fiction? Well, engineers at Johns Hopkins University in Baltimore, Maryland and mathematicians at Brown University in Providence, Rhode Island have found a way for polyhedra (many-sided structures) to fold and assemble themselves. With support from the National Science Foundation, Brown University mathematician Govind Menon and Johns Hopkins University chemical and biomolecular engineer David Gracias are developing self-assembling 3-D micro and nanostructures for a number of applications, including medicine.
The personalized delivery of an anticancer drug to a tumor, for example, has virtually no global side effects unlike the whole body chemotherapy treatments of today. It's like pouring salt on a slug on the sidewalk to kill it instead of spreading salt over the entire yard.
Check out this video to see how the addition of heat causes 2D polyhedral nanostructures assemble into hollow 3D structures. Go science!