Helical magnetic nano-machines with chiral plasmonics

Abstract

Magnetic micro/nano-machines, driven by external magnetic fields, offer promising applications in drug delivery, disease treatment, and biological research due to their precise controllability and biocompatibility. However, moving through the blood vessel requires nano-machines smaller than 500 nm, which not only exhibits strong Brownian motion so limited propulsion, but is also difficult to track them against blood cells and others. To overcome these challenges, this study introduce 250 nm long FePt helical nanomachines that are magnetically as well as chiroptically active, respectively enabling their propulsion and optical tracking against blood. We here explore their chiroptical properties theoretically and experimentally to track the motion of individual nano-machines. Furthermore, their actuation performances are evaluated under external magnetic fields, yielding the speed of 3.2 bodylength/s.