Enhanced and long-term CT imaging tracking of transplanted stem cells labeled with temperature-responsive gold nanoparticles.

Gold nanoparticles (AuNPs) have been extensively employed for computed tomography (CT) imaging in cell labeling and tracking because of their strong X-ray attenuation coefficient and excellent biocompatibility. However, the design and synthesis of stimuli-responsive AuNPs to modulate their endocytosis and exocytosis for optimal cell labeling and tracking are promising but challenging. Herein, we report an innovative labeling strategy based on temperature-responsive AuNPs (TRAuNPs) with high cell labeling efficiency and extended intracellular retention duration. We have manifested that the TRAuNP labeling imposes a negligible adverse effect on the function of human mesenchymal stem cells (hMSCs). Further experiment with idiopathic pulmonary fibrosis (IPF) model mice has demonstrated the feasibility of TRAuNP labeling for long time CT imaging tracking of transplanted hMSCs. What's more, the survival of transplanted hMSCs could also be monitored simultaneously using bioluminescence imaging after the expression of luciferase reporter genes. Therefore, we believe that this dual-modal labeling and tracking strategy enables visualization of the transplanted hMSCs in vivo, which may provide an important insight into the role of stem cells in the IPF therapy.