It can be very difficult to manipulate things on the nanoscale for the obvious reason that everything is so small. However, difficult is not the same as impossible, and researchers at Aalto University and the University of Washington have demonstrated that by finding a means to bend flat nanoscale objects into 3D structures with great precision.
While the tools we use on our scale cannot always be translated to the nanoscale, some of the effects we witness can be, including width-dependent curving. As the researchers describe, if you cut the stem of a dandelion flower into strips, and place the strips in water, they will bend at different angles, depending on the width of the strip. This is because of how much water is absorbed on one side of the stripe, compared to the other. The researchers realized that this could be replicated on the nanoscale with ion beams, because some materials react more to ions than others. By carefully aiming the beam, the material can be made to bend in only certain spots.
Potentially this bending technique could be used to trap and hold small particles within the structure's grasp. However, the potential for making these sturdy structures is hard to guess, especially as a comprehensive theory of how the processes involve operate has yet to be developed.