Figure 4.
Visible, magnetically-induced aggregates of MNPs that formed in suspension decreased in size with increasing distance from the magnet. (a) Total sizes (area; μm2) of clusters of particle aggregates measured from the bright field images of particle suspension within 4 mm (0.1, 0.5, 1, 2, and 4 mm) from the magnet are displayed as a function of time (5–180 min) under the magnetic field. (b) MNP concentration changes at each segment in the tube (0.1–0.5, 0.5–2, 2–4, and 4–7 mm from the magnet) are plotted as a function of time (5–180 min) under the external magnetic field (0.412 mg Fe/ml).