Two dimensional magnetic manipulation of microdroplets on a chip

In this paper we describe the two-dimensional (2D) magnetic manipulation of aqueous droplets suspended in silicone oil over the chip surface. The magnetic actuation is based on the force imposed on superparamagnetic microparticles inside the droplets. These can be displaced, merged, mixed and separated by changing the topology of the magnetic field created by a multilayer set of coils. The magnetic manipulation forces are generated on our chip without the use of external moving magnets. Our results demonstrate the potential of the proposed system in droplet-based biomedical analysis methods on a chip.