Nanotronics advisor Eric Drexler would say the only things stoping additive manufacturing from becoming a reality are "classical engineering problems" all the technology already exists. There must also be an evolution in process control technologies along with the process itself.
Video: Filtering Drinking Water with Nanofibers
This water bottle filter, made from nanofibers, can reduce water-borne diseases.
Quantum dot replaces metallic 'island' to improve electronic turnstile
(Phys.org)—A team of researchers with members from France, Russia and Finland has improved on the current design of an electronic turnstile, by replacing the conventional metallic "island" with a quantum dot. In their paper published in Physical Review Letters, the team describes how the design works, why it is better than the conventional approach and how much the error rate was reduced.