Mesoporous Silica Nanoparticles as a Delivery System of Gadolinium for Effective Human Stem Cell Tracking

The progress of using gadolinium (Gd)‐based nanoparticles in cellular tracking lags behind that of superparamagnetic iron oxide (SPIO) nanoparticles in magnetic resonance imaging (MRI). Here, dual functional Gd‐fluorescein isothiocyanate mesoporous silica nanoparticles (Gd‐Dye@MSN) that possess green fluorescence and paramagnetism are developed in order to evaluate their potential as effective T1‐enhancing trackers for human mesenchymal stem cells (hMSCs). hMSCs are labeled efficiently with Gd‐Dye@MSN via endocytosis. Labeled hMSCs are unaffected in their viability, proliferation, and differentiation capacities into adipocytes, osteocytes, and chondrocytes, which can still be readily MRI detected. Imaging, with a clinical 1.5‐T MRI system and a low incubation dosage of Gd, low detection cell numbers, and short incubation times is demonstrated on both loaded cells and hMSC‐injected mouse brains. This study shows that the advantages of biocompatibility, durability, high internalizing efficiency, and pore architecture make MSNs an ideal vector of T1‐agent for stem‐cell tracking with MRI. Designer Label: Dual‐functional Gd‐FITC mesoporous silica nanoparticles (Gd‐Dye@MSN) displaying green fluorescence and paramagnetism are developed as a label for human mesenchymal stem cells (hMSCs). Labeled hMSCs can be easily MRI‐detected in vivo with a clinical 1.5‐T MRI system (see image).