Iron labeling of mesenchymal stem/stromal cells for magnetic resonance imaging: studies on Poly-L-Lactic Acid-Iron nanoparticles
LicenseStandard (Fassung vom 01.10.2008)
In this thesis it could be consistently demonstrated with different methods [transmission electron microscopy (TEM), confocal laser scanning microscopy (CLSM), Prussian blue staining, flowcytometry (FACS), magnetic resonance imaging (MRI)] that iron-poly-L-lactic acid (iron-PLLA) nanoparticles synthesized with sodium n-dodecyl sulfate (SDS) as a surfactant with the miniemulsion process are intracellular located in mesenchymal stem/stromal cells (MSCs) (located in endosomes) and are taken up in MSCs rapidly (70 % in the first 2 h in a 24 h incubation period). They show no saturation of uptake in MSCs with increased concentration in the doses tested and show intracellular persistence in MSCs up to 144 h after particle removal as tested in two different incubation regimens. These iron-PLLA nanoparticles do not impair MSC viability as measured by 7-amino actinomycin D (7-AAD) staining directly after incubation up to 144 h after particle removal and do not change MSC line differentiation potential and phenotype. Iron-PLLA labeled MSCs do change MR signal even 96 h after particle removal, so that 200 000 and 50 000 cells/ml can be clearly discerned in the agarose phantom in a clinical grade 3T MRI scanner. Among several particles tested, decisive tests were done with MU119-5zdzN3+N4 which qualifies as suitable for further testing in vivo. From the results also information for further improvement in particle development and synthesis can be concluded (i.e. use of SDS as non-toxic surfactant, high negative surface charge, iron oxide concentration in the particle, use of iron oxides with improved magnetic properties).
Subject HeadingsMesenchymzelle [GND]
Magnetic resonance imaging [MeSH]
Mesenchymal stem cells [MeSH]