Nanoparticle labeling of mesenchymal stem cells for in vivo imaging and tracking

Stem cells can differentiate into multiple cell types, and thus have the potential to be used for tissue repair and regeneration. However, the participation of stem cells in wound repair and neovascularization is not well understood. As a result, there is a need to monitor and track stem cells in vivo in order to obtain a better understanding of the mechanisms of the wound healing response. Noninvasive, long-term imaging is ideal in order to track stem cells within a single animal model. Thus, we are interested in developing an imaging approach to track gold nanoparticle loaded mesenchymal stem cells (MSCs) in vivo after delivery via a hydrogel. This study assessed the effect on cell function of loading MSCs with gold nanoparticles. We examined the loading of MSCs with gold nanoparticles of various sizes and surface coatings using darkfield microscopy. We also examined the effect of nanoparticle loading on cell viability, proliferation, and differentiation. The feasibility of imaging nanoparticle loaded MSCs was examined by assessing cell viability and MSC tubulogenesis following laser irradiation. Our results demonstrate that loading MSCs with gold nanoparticles does not compromise cell function. These findings lend to the possibility of imaging MSCs in vivo with optical imaging.