Fabrication process of microtubes by rolled-up nanotech. During the first step (photolithography) (A), the photoresist is spin-coated onto a substrate, prebaked, and exposed to UV light through a mask before it is developed. During the electron beam evaporation (B), the nanomembranes are deposited on an angle onto the sacrificial photoresist layer. The roll-up (C) is achieved by etching the sacrificial layer. (B) and (C) modified from ,.