Long-term in vivo CT tracking of mesenchymal stem cells labeled with Au@BSA@PLL nanotracers
Human mesenchymal stem cells (hMSCs) transplantation has attracted considerable interest for treatment of pulmonary injury. Noninvasive and long-term tracking of hMSCs after transplantation in vivo that is important for our understanding of the stem cell therapy still remains a big challenge. Herein, we report on development of a novel gold nanoparticles-based nanotracer to track by CT imaging the transplantation hMSCs in vivo. The gold nanoparticles (AuNPs) was synthesized on bovine serum albumin (BSA) via in-situ growth method, and modified with poly-L-lysine (PLL) layer, yielding the nanotracers Au@BSA@PLL with enhanced biocompatibility and intracellular uptake. Au@BSA@PLL nanotracer was explored for in vitro and in vivo tracking of hMSCs with computer tomography (CT). Our results showed that the endocytosis of Au@BSA@PLL by hMSCs was as high as ~293 pg per cell. Meanwhile, the nanotracer had negligible influence on the viability, proliferation, and osteogenic and adipogenic differentiation of the labeled hMSCs. Using a pulmonary fibrosis injury mouse model induced by bleomycin, the labeled hMSCs could be tracked by CT imaging up to 23 d after transplanted in vivo, suggesting the feasibility of Au@BSA@PLL as a potential cellular nanotracer for noninvasive and long-term CT tracking of hMSCs in lung tissue repair.