Rod-shaped nanomotor powered by magnetic field gradients and its application to surface-enhanced Raman-scattering-based detection

Magnetically powered nanomotors have received increasing attention for decades because of their diverse potential applications. Here, we demonstrate a rod-shaped Au–Ni bimetallic nanomotor that can be powered by the gradients of applied magnetic fields. Efficient and steady control of locomotion over the Brownian motion is achieved by modulating the magnetic field and tailoring the length of Ni and Au segments. The nanomotors are ideal for use as a dynamic surface-enhanced Raman scattering (SERS) sensor platform, in that the average enhancement is up to almost one order of magnitude higher than that in a conventional nanostructured Au substrate, thus providing a promising alternative for real-time biochemical sensing.