Self-rolled polymer tubes: novel tools for microfluidics, microbiology, and drug-delivery systems.

Recent work on the fabrication of tubular microstructures via self-rolling of thin, bilayer polymer films is reviewed. A bending moment in the films arises due to the swelling of one component of the bilayer in a selective solvent. The inner diameters of the tubes vary from hundreds of nanometers to dozens of micrometers. The position of the tubes on the substrate and their length can be preset by photolithographic patterning of the bilayer. Prior to rolling, the bilayers can be exposed to different methods of surface functionalization, providing opportunities for engineering the microtube inner surfaces for use in microfluidic circuits and "microbiological" applications. The self-rolling approach is promising for the development of novel drug- and cell-delivery systems, as well as for tissue engineering.