A simple synthesis of superconductor nanowires (see figure) is carried out by rational design of the synthetic protocol. This technique is based on the selection of a component (in this case BaCO3) that remains invariant throughout the synthesis. A biopolymer matrix ensures antisintering of BaCO3 nanoparticles, leading to single-crystal outgrowth of the superconductor in this most technologically useful of morphologies.