A core-shell nanowire, a method of forming the core-shell nanowire and a stretchable composite comprising the core-shell nanowire are provided. The core-shell nanowire comprises a core comprising a conductive metal and a shell comprising a biocompatible metal. The method of forming the core-shell nanowire comprises a step of forming a core-shell nanowire by carrying out epitaxial growth of a biocompatible metal on a surface of a core comprising a conductive metal. The stretchable composite comprises a first core-shell nanowire/polymer composite comprising first core-shell nanowires and a first polymer, a first insulating layer disposed on the first core-shell nanowire/polymer composite, and a second core-shell nanowire/polymer composite disposed on the first insulating layer and comprising second core-shell nanowires and a second polymer.
