Figure 3.

Effect of Gd-DTPA on diamagnetic cell printing. Formation of 3D and multidimentional cell structures (2.5D) through diamagnetophoresis on (a) a ULA surface and (b) a TCT surface. Approximately 1000 cells (n=5 analyzed by SD) are incubated in both cases. For (a, i), 0 and 1 mM Gd-DTPA are insufficient to coalesce cells into a 3D structure. At 24 hours, accumulation of numerous globular cluster aggregates is observed. Only 25 and 10 mM Gd-DTPA are able to print cells through diamagnetophoresis. (a, ii) As the concentration of Gd-DTPA decreases from 25 mM, the formation of globular cell clusters increases and their ability to form a single spherical 3D structure is reduced. Only 25 mM is able to produce a single spherical cluster that remained intact until 24 hours. For (b, i), concentrations of 0 and 1 mM are again insufficient to coalesce cells into a 3D structure. The diameters of the cellular structures are equivalent those of their wells since these cells have formed 2D monolayers. Only 10 and 25 mM Gd-DTPA were able to produce a 3D structure; however, for (b, ii) 25 mM Gd-DTPA produced a denser 3D structure. Therefore, 25 mM Gd-DTPA is an appropriate concentration for forming 3D cell structures using diamagnetophoresis. Scale bar = 50 μm.