Fig. 2.

Magnetic field alignment of SPIONs. (A) Finite element modeling of the magnetic field strength and distribution. (B) Time-lapse images showing the magnetic field alignment of SPIONs (brown) in water, with a clear transition from a biphasic stack to a smooth gradient. (C) Bright field microscopy images showing gradients of SPIONs (brown) immobilized in different biomaterials. Scale bar in all images = 2 mm. (For interpretation of the references to colour in this figure legend, the reader is referred to the Web version of this article.)