Figure 1.

(A) Captured video frame of the microfluidic junction for droplet generation (Video S1). The ferrofluid phase (top, discontinuous phase) is separated into homogeneous nanoliter droplets by the HFE oil phase (continuous phase, left side), accomplished by a T-junction geometry, and guided through the main channel (right side, emulsion phase). (B) Conceptual illustration of the combination of the two technologies, namely, droplet microfluidics (ferrofluid droplets in the HFE oil carrier phase) and PHE-based sensorics. (C) Large-scale SEM image of the PHE sensor center. The change of the in-plane voltage (V_xy) is measured perpendicular to the applied current I. (D) Time evolution of the transversal resistance of the PHE sensor (bottom) of passing superparamagnetic droplets (top).