Lipophilic Near-Infrared Dyes for In Vivo Fluorescent Cell Tracking

Cells can be easily and noninvasively tracked in the body by labeling them with a lipophilic, near-infrared dye and using a live fluorescence imaging system to image the position of the dye in the body. Near-infrared dyes provide several advantages, primarily that tissue is mostly highly transparent to near-infrared light, resulting in clearer and more accurate images. Briefly, cells are labeled with a near-infrared dye such as DiR and injected into a disease model. The model is then imaged using the live fluorescence imaging system on an hourly and/or daily basis to track cell migration and final location. The relative number of cells that migrate to the desired location can be measured by measuring the fluorescent intensity at the location versus elsewhere in the body. This paper describes a method for using DiR dye to label and track C17.2 neural progenitor cells to a murine model of mammary carcinoma.