Figure 9.

T₂-weighted contrast MR images of various IONPs. (A) Schematic illustration of the ball models of octapod and spherical IONPs with the same geometric volume, smooth M-H curves, T₂-weighted MR images, and comparison of r₂ values of IONPs with different diameters: Octapod-30 (~58 nm), Octapod-20 (~49 nm), Spherical-16 (~30 nm) and Spherical-10 (22 nm). Reproduced with permission from ³², copyright 2013. (B) TEM images, r₂ values and T₂-weighted MR images of different IO clusters C1-C3 (C1: ~115.5nm; C2: ~127.8 nm; C3: ~129.2 nm), as well as the single IO-5 (~5.2 nm) and IO-15 (~15.1 nm) NPs. Reproduced with permission from ¹³³, copyright 2017. (C) The MR contrast effect of Fe₃O₄ NRs of different lengths and NPs of different diameters. Reproduced with permission from ¹³², copyright 2015.