In this article, we review recent work on the co-electrospinning of polymer core-shell nanofibers and the manufacture of hollow nanotubes. The encapsulation and release of bioactive compounds from co-electrospun core-shell fibers is considered next, bearing in mind such applications as sensors and drug release. Then, nanofluidic phenomena in nanotubes made via co-electrospinning (as well as via the other processes) are discussed. We also consider dielectrophoresis in microchannels as a possible tool for the separation of viruses, nanoparticles and macromolecules.