Fig. 1.

Neutrophil-inspired propulsion based on acoustic and magnetic field actuation. a Neutrophil rolls on vasculature before transmigrating into tissue. b Superparamagnetic particles aggregate due to dipole–dipole interaction in the presence of a magnetic field (i). The aggregate migrates towards the wall due to the radiation force in an acoustic field (ii). A rolling-type motion along the boundary is achieved by combining both fields. The assembled entities disassociate when the magnetic field is turned off