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 ( 89 Zr)-labeled mesoporous silica nanoparticles ( 89 Zr-mSiO 2 ) as a robust platform for cell tracking via positron emission tomography (PET) imaging. The designed 89 Zr-mSiO 2 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 89 Zr-mSiO 2, ensuring reliable and safe cellular labeling. Notably, 89 Zr-mSiO 2 exhibits negligible cell efflux, enabling precise detection of cellular signals without interference. PET imaging of 89 Zr-mSiO 2 -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 89 Zr-mSiO 2 as a promising tool for long-term in vivo tracking of functional cells, thus advancing the prospects of cell therapy in a clinical setting.