Nanotech News

July 18, 2005

Two Labels Double Versatility of Nanoparticles for Tracking Cells

An informative – and difficult – cancer-related event to track is the travels of an individual migrating cell, such as a metastatic cancer cell or immune system cell, within the body. Labeled magnetic nanoparticles have proven somewhat useful in this regard, enabling researchers to track cell movement within the body using magnetic resonance imaging (MRI), but MRI cannot pinpoint one cell’s location with enough spatial detail to satisfy investigators’ needs.

To overcome this limitation, a team of academic and government researchers has developed a polymer nanoparticle containing two imaging labels, one visible via MRI, the other a fluorescent label that can be viewed using high-resolution optical imaging. The result is a nanoparticle that researchers can use to label individual cells and track their movement within the body with significantly higher spatial detail than was possible with previously developed methods.

Writing in the journal Bioconjugate Chemistry, a research team headed by Samira Guccione, Ph.D., at Stanford University, detailed its method for preparing nanoparticles containing both gadolinium and rhodamine on their surface. The polymer nanoparticles, 85 nanometers in diameter, were readily and rapidly taken up by breast cancer cells growing in tissue culture and had no apparent impact on the viability or behavior of the labeled cells. When injected into mice, the labeled cells were clearly visible in both whole-body MRI and optical imaging scans for up to seven days. The researchers note that labeled cells can also be identified easily when tissues are removed for detailed histological examination using fluorescence microscopy.

This work is detailed in a paper titled, “Gadolinium-rhodamine nanoparticles for cell labeling and tracking via magnetic resonance and optical imaging.” Investigators from the National Cancer Institute, the Howard Hughes Medical Institute-National Institutes of Health Research Scholars Program, the National Institutes of Health, and the National Institute of Biomedical Imaging and Bioengineering participated in this study. This paper was posted online in advance of print publication.

An abstract is available at the journal’s website.
View abstract.