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Updated: Jun 5, 2026

Labeling hESCs and hMSCs with Iron Oxide Nanoparticles for Non-Invasive in vivo Tracking with MR Imaging
Published on: March 31, 2008
Thiolated polyacrylic acid-modified iron oxide nanoparticles for in vitro labeling and MRI of stem cells
A Vetter1, A Reinisch, D Strunk
1Department of Pharmaceutical Technology, Institute of Pharmacy, Leopold-Franzens-University Innsbruck, Innsbruck, Austria.
Purpose:
The purpose of this study was to develop and characterize new surface-modified iron oxide nanoparticles demonstrating the efficiency to be internalized by human endothelial progenitor cells (EPCs) from umbilical cord blood.
Methods:
Iron oxide nanoparticles were coated with polyacrylic acid-cysteine (PAA-Cys) by either in situ precipitation or postsynthesis. The nanoparticles were characterized by X-ray powder diffraction. EPCs were labeled with PAA-Cys-modified iron oxide nanoparticles or with uncoated nanoparticles. The relaxivity of uncoated and coated iron oxide nanoparticles as well as EPCs labeled with PAA-Cys-modified iron oxide were determined.
Results:
Addition of PAA-Cys increased the particle size from 10.4 to 144 and 197 nm, respectively. The X-ray powder diffraction pattern revealed that the particles consist of Fe(3)O(4) with a spinal structure. Postsynthesis coated particles showed a cellular uptake of 85% and 15.26 pg iron/cell. For both types of particles the relaxivity ratio was at least 2-fold higher than that of the gold standard Resovist(®).
Conclusion:
The PAA-Cys coated iron oxide nanoparticles are a promising tool for labeling living cells such as stem cells for diagnostic and therapeutic application in cell-based therapies due to their high relaxivities and their easy uptake by cells.
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