Fig. 1
Reprinted from [30]. c FEM-based simulation of the magnetic field generated by the magnets used in the experimental device by the permanent magnets (PM).
a Configuration of the magnets in the experimental device and its working principle. A couple of magnets are symmetrically placed on the sides of the silicone tube and are moved along following the curvilinear geometry. b Experimental realization of MNP magnetic confinement in a capillary having the same diameter as the internal lumen of the silicone tube used in the experiments. The MNP plug is contained in a 250 μm long section of a 500 μm wide capillary and thus has a volume of 50 nl. Bar is 3 mm long corresponding to the edge-to-edge distance between magnets. The image is oriented as in c. For imaging purposes, the magnetically confined MNP plug is shown in a completely transparent quartz capillary suspended between the magnets.