Sep 16, 2009
Fluorescent nanoparticles enhance stem-cell tracking
For cellular MRI there is a need to label cells with superparamagnetic iron oxide nanoparticles (SPION) that have multiple imaging moieties, which are non-toxic and have increased NMR relaxation properties to improve the detection and tracking of therapeutic cells. Although increases in the relaxation properties of SPION have been accomplished, detection of tagged cells is limited by either poor cell labelling efficiency or low intracellular iron content.
In a recent cell-labelling study, which was published in the journal Nanotechnology, the authors reported a simple strategy via a complex formation with peptide to overcome these obstacles. In their paper, the researchers studied a complex formation between negatively charged fluorescent mono-disperse SPION and a positively charged peptide systematically and theoretically, and used the complex formation to improve the MR properties of labelled stem cells.
The team demonstrated that the theoretical approach of SPION-peptide complexes could provide guidelines for cell labelling and possibly predicting NMR relaxation properties of labelled cells in vitro. Magnetic labelling of cells with fluorescent mono-disperse SPION-peptide complexes provided greater changes in signal intensity on T2* weighted images of magnetically labelled cells compared with other SPION-peptide complexes.
The finding that human mesenchymal stem cells (hMSCs) stay intact in flank tumours after seven days holds promise for the detection of stem cells in tissue. The group believes that the developed FL SPION-peptide complex will have a great impact on monitoring stem-cell migration for cell therapy in the future.
About the author
The work was conducted at the Frank Laboratory, National Institutes of Health. Jae-Ho Lee is a postdoctoral fellow developing nano drug-delivery carriers and contrast agents currently under Dr Blumenthal's mentorship on the CCR Nanobiology Program, National Cancer Institute of Health at Frederick. Melissa A Smith and Eric M Gold are post-bachelor students. Wei Liu is a PhD researcher in Philips Research North America. Bobbi Lewis is a researcher at the Frank Laboratory. Ho-Taek Song is an assistant professor at Yonsei University. Joseph A Frank is the chief of the Frank Laboratory.