Magnetically-controlled, pulsatile drug release from poly(ε-caprolactone) (PCL) particles with hollow interiors

Shrinkage of an interior void: When exposed to an external AC magnetic field, Fe3O4 NPs entrapped in the shells of PCL hollow particles will raise the local temperature of the polymer particles, which makes the interior void shrunk. This shrinkage can pump out water filling the interior void, together with the preloaded drug molecules from the hollow interior.256