Controllable Assembly of Hydrophobic Superparamagnetic Iron Oxide Nanoparticle with mPEG-PLA Copolymer and Its Effect on MR Transverse Relaxation Rate
Figure 4
MR relaxation property of SPION clusters, these size distributions and comparison of the relaxation rates with theoretical predictions (d). (a) Relaxation rates of SPION clusters as functions of iron concentrations. (b) Size distribution of SPION clusters evaluated with volume-weighted method. (A) loosen SPION clusters (LSC): 58 nm. (B)–(F), condense SPION clusters (CSC): 73 nm, 95 nm, 97 nm, 144 nm and 199 nm, respectively. (c) Size distribution of SPION clusters evaluated with number-weighted method. (A) loosen SPION clusters (LSC): 43 nm. (B)–(F), condense SPION clusters (CSC): 48 nm, 59 nm, 76 nm, 85 nm and 113 nm, respectively. (d) Comparison of relaxation rates of SPION clusters with theoretical predictions with sizes evaluated with TEM or DLS (number-weighted and volume-weighted). The straight lines are fair approximations of the theoretical predictions (MAR, SD and ELR). Loosen SPION clusters (LSC) demonstrate the smallest sizes and relaxation rate.
