Medical systems, including guide wires and guide wire assemblies 1100, 2100, 3100 that are configured such that a flexibility of the guide wire can be changed or modified. In various embodiments, the flexibility of the guide wire can be changed or modified in-situ. The guide wires and/or guide wire assemblies of the disclosed medical systems may include materials having material properties that can be modified in association with exposing one or more portions of the medical system, such as one or more components of the guide wire or guide wire assembly to electric current.
