Dynamic magnetic particle actuation for rapid biosensing

Upcoming generations of highly sensitive and miniaturized biosensing systems need target capture methods that are as efficient and as rapid as possible. Magnetic particles can be used to efficiently capture targets from liquid. We show that target capture can be accelerated by at least one order of magnitude by using time-dependent magnetic fields that actuate ensembles of magnetic particles. Furthermore we exploit the repulsive magnetic dipole-dipole interaction between particles near a surface, in order to undo magnetically-induced aggregation of particles and retrieve single particles for further assaying. By combining the approaches, a novel assay concept is proposed in which dynamic magnetic particle actuation is used across all assay steps.