Nanoparticles for in-vivo cell tracking
Cell therapy provides a promising approach for diseases and injuries that conventional therapies cannot effectively cure . These include T cells for cancer immunotherapy, and stem cells for treating conditions such as neurodegenerative diseases, heart disease, muscular dystrophy and diabetes. However, the application of cell therapy in routine clinical practice is challenging, as clinical trials have shown highly contradictory results. To implement cell therapy, the mystery regarding the fate of the transplanted cells must be uncovered. To answer this need, we developed a novel method for longitudinal and quantitative in vivo cell tracking, based on the superior visualization abilities of classical X-ray computed tomography (CT), combined with gold nanoparticles as labeling agents. With our technique we were able to track stem cells as they home to damaged areas within the brain and to track cancer-specific T-cells as they migrate to the tumor. We found that uniting the superior visualization abilities of classical CT with state-of-the-art nanotechnology were the key for high-resolution cell tracking. For cell quantification, we developed a non-invasive quantitative CT ruler, which can be used to determine the number of cells residing in a specific region, without tissue destruction or animal scarification. We have further investigated the design principals and capabilities of this technique for intramuscular transplantation of therapeutic cells. Longitudinal studies were performed, displaying the ability to track cells over long periods of time (one month) while maintaining cell functionality. The detection limit was determined and a way to quantify the number of cells visualized by CT was demonstrated. In the future, this technology has the potential to be applied clinically and to serve as an early warning system for patients after cell transplantation.