Tour pointed to hemoglobin as an example. Each heme group -- containing one iron atom -- carries only one molecule of oxygen, but billions of them go back and forth carrying oxygen from our lungs to the cells crying out for it. And on the way back out of the cells, the hemes detoxify by carrying out CO2. In the same way, nanovehicles could carry atoms to construct objects.

While self-assembling machines have been theorized for years, Tour argues that they can't succeed in creating complex structures, such as metals, because complex structures have many irregular segments to them.

"For example, nature builds by self-assembly but also by enzymatic assembly. Enzymes are natures nanomachines. They take molecules and stitch them together in nonperiodic patterns," Tour said. "That's what you need for complex assembly."

While enzymes don't work well outside of a biological host, if nano-size machines can be built that can pick up small objects like a molecule, bring them into place, attach them, and then go and pick up another one and put that in place, "then we can do exactly what enzymes do," he said.

There are three types of nanotechnology construction: passive, hybrid and active. Today, passive nanotechnology is being used with carbon nanotubes, which can greatly enhance the toughness of rubber, for example, or create pathways for bits of data.