Magnetotactic artificial self-propelled nanojets.

Self-propelled catalytic bubble-ejecting nanotubes (nanojets) are expected to perform a variety of autonomous tasks. Herein, we will show that with the introduction of a Ni segment into the Au/Ni/Pt nanotube design followed by consequent magnetization a permanent change in the magnetic domain orientation of the Ni segment can be induced. Consequently, this results in the presence of a permanent magnet within the nanojet with its north/south domains oriented along the tube axis. Such a magnetized nanojet orients itself according to the external magnetic field and propels itself toward or away from the source of the magnetic field depending on its orientation. This behavior is similar to that of the magnetotactic bacteria. The ability to sense the magnetic field is expected to have a strong impact on future applications of autonomous self-propelled nanojets.