Permalloy-coated tungsten probe for magnetic manipulation of micro droplets

摘要

In this work, we present the magnetic manipulation of biocompatible droplets using a probe-based approach. First, we describe a simple method to develop magnetic probes that are capable of delivering localized magnetic fields, which is important for precise manipulation. The fabrication of magnetic probes involves controlled electroplating of permalloy (Ni80Fe20) on commercially available tungsten needles with tip radii as small as 0.5 μm. Experimental validation of probe functionality was achieved by characterizing the magnetic response of the probe with a highly sensitive scanning Hall probe system. The magnetic probe was then employed in manipulating biocompatible alginate micro droplets with encapsulated magnetic particles. The synthesis of the droplets was carried out in-house and droplets of different sizes and magnetic particle concentrations were obtained for use in manipulation experiments. Multiple experiments were done to demonstrate the efficacy of the developed probe in manipulating droplets, which is crucial for constructing droplet-based microfluidic systems.