Adult stem cells are also under investigation in therapies that enhance new blood vessel growth to improve the blood supply to diabetic patients' limbs or to repair blood vessels after a heart attack or bypass surgery. Tracking nanoparticle-labeled cells used in such treatments by MRI imaging would allow physicians to monitor the treatment's success or failure.
The nanoparticles ?called "nano" because they measure only about 200 nanometers across, or 500 times smaller than the width of a human hair ?are made up largely of perfluorocarbon, a safe compound used in artificial blood. The fluorine atoms in the particles can be detected by tuning an MRI scanner to the unique signal frequency emitted by the perfluorocarbon compound used.
Since several perfluorocarbon compounds are available, different types of cells potentially could be labeled with different compounds, injected and then detected separately by tuning the MRI scanner to each one's individual frequency, says Wickline.
That makes the labeled cells potentially useful for vascular research as well. "Many kinds of cells are involved in the formation of new blood vessels," Partlow says. "Because we can create a separate MRI signature for different cells with these various types of unique nanoparticles, we could use them to better understand each cell type's role."
The nanoparticles are very compatible with living cells, according to the research findings. "The cells just take these particles in naturally ?no special sauces have to be added to make them tasty to these cells," says Wickline, also professor of medicine, of physics and of biomedical engineering and a Washington University heart specialist at Barnes-Jewish Hospital. "And then the cells just go about their business and do what they're supposed to do
Source:Washington University School of Medicine