Veronica Clavijo Jordan1, Michael R. Caplan1, Kevin M. Bennett1
We report a protein based nanoparticle with a Fe3O4 crystal core and Mn2+ bound to surface channels. The metal core size ranged from 3 to 6nm in diameter, and ICP results indicate 7 Mn2+ per protein. HRTEM shows that the core metal is magnetite with a lattice spacing of 0.25nm. Following the proposed synthesis, we suspect that the high per-ion T1 (338mM-1s-1) and T2 (133 mM-1s-1) relaxivity are due to a cooperative effect contributed by the Mn2+ and the Fe3O4 crystal. MRI scans of rat brain inoculations show it can be detected in vivo.