To the delight of researchers at Washington University School of Medicine in St. Louis, living cells gobbled up fluorine-laced nanoparticles without needing any coaxing. Then, because of the unusual meal, the cells were easily located with MRI scanning after being injected into mice.
Developed in the laboratories of Samuel A. Wickline, M.D., and Gregory Lanza, M.D., Ph.D., the nanoparticles could soon allow researchers and physicians to directly track cells used in medical treatments using unique signatures from the ingested nanoparticle beacons.
In an article that will appear in the June issue of the FASEB Journal, lead author Kathryn C. Partlow, a doctoral student in Wickline's lab, describes using perfluorocarbon nanoparticles to label endothelial progenitor cells taken from human umbilical cord blood. Such cells can be primed to help build new blood vessels when injected into the body. The researchers believe nanoparticle-labeled stem cells like these could prove useful for monitoring tumors and diagnosing and treating cardiovascular problems.
The nanoparticles contain a fluorine-based compound that can be detected by MRI scanners. Fluorine is most commonly known for being an element included in fluoride toothpastes. Wickline, who heads the Siteman Center of Cancer Nanotechnology Excellence, says this technology offers significant advantages over other cell-labeling technologies under development.
"We can tune an MRI scanner to the specific frequency of the fluorine compound in the nanoparticles, and only the nanoparticle-containing cells will be visible in the scan," he says. "That eliminates any background signal, which often interferes with medical imaging. Moreover, the lack of interference means we can measure very low amounts of the labeled cells and closely estimate their number by the brightness of the image."