In 2007, productive nanosystems were defined as functional nanoscale systems that make atomically-specified structures and devices under programmatic control, i.e., performing atomically precise manufacturing.
[1] As of 2015, such devices were only hypothetical, and productive nanosystems represented a more advanced approach among several to perform Atomically Precise Manufacturing.
As of 2018, it was also possible to build very small atomically precise structures using scanning probe microscopy to construct molecules such as FeCO[3] and Triangulene, or to perform hydrogen depassivation lithography.
Principles of physics and examples from nature both suggest that it will be possible to extend atomically precise fabrication to more complex products of larger size, involving a wider range of materials.
Passive nanostructures - nanoparticles and nanotubes that provide added strength, electrical and thermal conductivity, toughness, hydrophilic/phobic and/or other properties that emerge from their nanoscale structure.