|Title:||Microgel iron oxide nanoparticles for tracking of stem cells through magnetic resonance imaging||Authors:||LEE SHOO MING||Keywords:||mri tracking, nanoparticles, mesenchymal stem cells, microgel, migration, stroke||Issue Date:||20-Aug-2009||Citation:||LEE SHOO MING (2009-08-20). Microgel iron oxide nanoparticles for tracking of stem cells through magnetic resonance imaging. ScholarBank@NUS Repository.||Abstract:||
Current markers for cellular labelling are composite, magnetic particles that measure less than 100 nm or greater than 1 micron in diameter. As the intermediate range has not been investigated, microgel iron oxide particles (MGIO) with the diameters of 89 to 765nm were synthesised and characterised in terms of their physical properties. The magnetic resonance relaxation characteristics of MGIO were measured and shown to largely agree with the values predicted by theoretical models.
The efficiency of MGIO was tested on human fetal mesenchymal stem cells (fMSC). With simple incubation, MGIO provided equal or better uptake in fMSC compared to a clinical particle, ferucarbotran, with MGIO-600nm achieving three-fold higher uptake. Labelled fMSC was characterised in terms of proliferation rate, multilineage differentiation capacity and global gene expression to show that labelling with MGIO does not affect stem cell functions. To further verify the safety of MGIO, human endothelial progenitor cells were labelled and shown to retain phenotype and function after labelling.
A rat stroke injury model was developed to observe cellular migration. Labelled-fMSC was transplanted intracerebrally or intraveneously and shown via MRI to home to the injury site. MGIO labelling provided superior detection of cells compared to ferucarbotran labelling. Histological analysis showed that MRI reliably detected the location of fMSC for up to 5 days post-transplantation after which fMSC were rejected by the host due to the nature of the animal model used. This study shows that MGIO is an efficient label that enables improved detection of transplanted cells during in vivo imaging.
In all, this thesis describes the development of a high contrast MRI cellular label with superior performance over commericially-available iron particles, with possible applications for in vivo tracking of transplanted stem cells.
|Appears in Collections:||Ph.D Theses (Open)|
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