Control of the interparticle spacing in superparamagnetic iron oxide nanoparticle clusters by surface ligand engineering

Wang Dan¹, Lin Bingbing¹, Shen Taipeng¹, Wu Jun¹, Hao Fuhua², Xia Chunchao³, Gong Qiyong³, Tang Huiru², Song Bin³, Ai Hua^{1, 3, †,}

The magnetic properties of SPIO clusters. (a), (c) Hysteresis loops of the SPIO nanoparticle containing micelles measured at 300 K (inset shows a zoomed-in plot between −2 kOe and 2 kOe magnetic field). (b), (d) T₂ relaxation rate (1/T₂, s⁻¹) as a function of iron concentration (mM) for SPIO micelles at 1.5 T. The M_s and T₂ relaxivities of SPIO clusters followed an descending trend with the increase of SPIO interparticle spacing.