Radiolabeled Mesoporous Silica Nanosystem Enables Long-Term Cell Tracking In Vivo

The clinical advancement of cell therapy necessitates precise in vivo tracking of functional cells, yet challenges persist in achieving this goal. Herein, we introduce zirconium-89 (89Zr)-labeled mesoporous silica nanoparticles (89Zr-mSiO2) as a robust platform for cell tracking via positron emission tomography (PET) imaging. The designed 89Zr-mSiO2 exhibits exceptional biocompatibility and internalization efficiency into cells, owing to its unique mesoporous structure and stable Si-O-Zr bonds. Both in vitro and in vivo studies demonstrate the prolonged stability and minimal cytotoxicity of 89Zr-mSiO2, ensuring reliable and safe cellular labeling. Notably, 89Zr-mSiO2 exhibits negligible cell efflux, enabling precise detection of cellular signals without interference. PET imaging of 89Zr-mSiO2-labeled cells in murine models allows for the real-time tracking of cell localization for up to 10 days postinjection. Overall, our findings highlight the potential of 89Zr-mSiO2 as a promising tool for long-term in vivo tracking of functional cells, thus advancing the prospects of cell therapy in a clinical setting.