Search

We describe an on-chip system to control the actuation of micrometer- and nanometer-sized magnetic particles. Orthogonal conducting microwire arrays are used to induce magnetic fields with highly localized peaks and strong local gradients. These fields are then applied in actuation experiments to generate defined particle movement with micrometer precision. We examine different types of current sequences to efficiently move and separate the particle cloud on the chip without the use of external magnets. The final protocol allows efficient and reliable control over the particle cloud's position minimizing the loss of particles during the individual switching steps. Schematic of a microwire chip controlling a cloud of particles (black). The chips are processed on silicon (blue). The microwires consist of Au (yellow) and are insulated with an oxide nitride passivation layer (green transparent).

Microwire arrays are a powerful tool for the exertion of localized thermal stress on cellular networks. Combining microwire arrays with a set of orthogonal axon-guiding microchannels on-chip allows for the positioning of neurites, as well as control over their polarity. In this paper, we present a new fabrication approach, based on standard clean room fabrication and sacrificial layer etching, for the integration of microwire arrays into neurite guiding structures. The system permits the application of strong temperature gradients, enabling localized thermal stimulation inside microchannels.