CT/Bioluminescence Dual-Modal Imaging Tracking of Mesenchymal Stem Cells in Pulmonary Fibrosis.

Human mesenchymal stem cells (hMSCs), due to their immune regulation and collateral secretion effects, are currently explored for potential therapy of idiopathic pulmonary fibrosis (IPF). Understanding the migration, homing, functions, and survival of transplanted hMSCs in vivo is critical to successful IPF treatment. Therefore, it is highly desired to develop noninvasive and effective imaging technologies to track the transplanted hMSCs, providing experimental basis for improving the efficacy of hMSCs in the treatment of IPF. The rational design and development of a dual-labeling strategy are reported by integrating gold nanoparticle (AuNP)-based computed tomography (CT) nanotracers and red-emitting firefly luciferase (RfLuc)-based bioluminescence (BL) tags for CT/BL multimodal imaging tracking of the transplanted hMSCs in a murine model of IPF. In this approach, the CT nanotracer is prepared by sequential coupling of AuNPs with polyethylene glycol and trans-activator of transcription (TAT) peptide (Au@TAT), and employed it to monitor the location and distribution of the transplanted hMSCs in vivo by CT imaging, while RfLuc is used to monitor hMSCs viability by BLI. This facile strategy allows for visualization of the transplanted hMSCs in vivo, thereby enabling profound understanding of the role of hMSCs in the IPF treatment, and advancing stem cell-based regenerative medicine.

Laser Ablated Albumin Functionalized Spherical Gold Nanoparticles Indicated for Stem Cell Tracking.

Cell tracking in cell-based therapy applications helps distinguish cell participation among paracrine effect, neovascularization, and matrix deposition. This preliminary study examined the cellular uptake of gold nanoparticles (AuNPs), observing cytotoxicity and uptake of different sizes and AuNPs concentrations in Adipose-derived stromal cells (ASCs). ASCs were incubated for 24 h with Laser ablated Albumin functionalized spherical AuNPs (LA-AuNPs), with average sizes of 2 nm and 53 nm in diameter, in four concentrations, 127 µM, 84 µM, 42 µM, and 23 µM. Cytotoxicity was examined by Live/Dead assay, and erythrocyte hemolysis, and the effect on the cytoskeleton was investigated by immunocytochemistry for ß-actin. The LA-AuNPs were internalized by the ASCs in a size and concentration-dependent manner. Clusters were observed as dispersed small ones in the cytosol, and as a sizeable perinuclear cluster, without significant harmful effects on the cells for up to 2 weeks. The Live/Dead and hemolysis percentage results complemented the observations that the larger 53 nm LA-AuNPs in the highest concentrated solution significantly lowered cell viability. The demonstrated safety, cellular uptake, and labelling persistency with LA-AuNPs, synthesized without the combination of chemical solutions, support their use for cell tracking in tissue engineering applications.