Magnetoplex based on MnFe₂O₄ nanocrystals for magnetic labeling and MR imaging of human mesenchymal stem cells

For efficient labeling and tracking via magnetic resonance (MR) imaging of human mesenchymal stem cells (h-MSCs), magnetic labeling agents must be responsive to an external magnetic field. Thus, we developed ultrasensitive magnetoplex as a magnetic labeling agent composed of PEGylated MnFe ₂O₄ nanocrystals (PMNCs) and polycationics (poly-L-lysine, PLL) for efficient labeling of the h- MSCs and monitoring of the transplanted h-MSCs for a long term. PMNCs were prepared by nanoemulsion methods composed of MnFe₂O₄ nanocrystals (MNCs) and amphiphilic polymers (mPEG-dodecanoic acid). The prepared PMNCs exhibited excellent biocompatibility and their polycationic complexes (PMNCs/ PLL) demonstrated remarkable sensitivity compared with magnetic iron oxide nanoparticles (MION)/PLL or Ferumoxides/PLL. Furthermore, PMNCs demonstrated the potentials for novel diagnostic and therapeutic strategies with potential applications in various biomedical fields.