Reflection optical microscope image of the dried suspension of lithographically defined 60-nm-thick, ~1 micron diameter 20:80 iron-nickel (permalloy) discs coated with a 5-nm-thick layer of gold on each side that possess a spin-vortex ground state. Under application of an alternating magnetic field the spin vortices shift, creating an oscillation. When the microdiscs are biofunctionalized and selectively attached to the cancer cell, such spin-vortex-mediated stimulus creates two dramatic effects: compromised integrity of the cellular membrane, and initiation of programmed cell death. Nature Materials, doi:10.1038/nmat2591.

Image courtesy: Dr. V. Novosad, Argonne National Laboratory.