Quantification of Cell Labeling with Micron-Sized Iron Oxide Particles Using Continuum Source Atomic Absorption Spectrometry

Abstract

Detection of cells after transplantation is necessary for quality control in regenerative medicine. Labeling with micron-sized iron oxide particles enables noninvasive detection of single cells by magnetic resonance imaging. However, techniques for evaluation of the particle uptake are challenging. The aim of this study was to investigate continuum source atomic absorption spectrometry (CSAAS) for this purpose. Porcine liver cells were labeled with micron-sized iron oxide particles, and the iron concentration of the cell samples was investigated by a CSAAS spectrometer equipped with a Perkin-Elmer THGA graphite furnace. The weak iron line at 305.754 nm provides only about 1/600 sensitivity of the iron resonance line at 248.327 nm and was used for CSAAS measurements. Iron concentrations measured from labeled cells ranged from 5.8 +/- 0.3 to 25.8 +/- 0.9 pg Fe/cell, correlating to an uptake of 8.2 +/- 0.5 to 25.7 +/- 0.8 particles/cell. The results were verified by standardized morphometric evaluation. CSAAS enabled rapid quantification of particle load from small quantities of cells without extensive preparation steps. Thereby, CSAAS could be used for quality control in a clinical setting of cell transplantation.

Serial monitoring of endogenous neuroblast migration by cellular MRI

“…Other non direct methods such as flow cytometry (Williams et al, 2007) or atomic absorption spectrometry (Raschzok et al, 2009) can only be performed on ex vivo samples. Phase map cross correlation is a new post processing data analysis technique that was recently developed to quantify localization and accumulation of SPIO particles (Mills et al, 2008).…”

In Vitro Evaluation of Magnetic Resonance Imaging Contrast Agents for Labeling Human Liver Cells: Implications for Clinical Translation

“…Details of the instrumentation and protocol are published elsewhere [26]. In brief, protein samples taken at culture days 1, 2, 4, and 6 were thawed, homogenized, and diluted 1:4 using deionized water.…”

Intramyocardial Transplantation and Tracking of Human Mesenchymal Stem Cells in a Novel Intra-Uterine Pre-Immune Fetal Sheep Myocardial Infarction Model: A Proof of Concept Study

“…However, utilizing a detailed in-vitro tissue evaluation and importantly, advanced super-paramagnetic agents such as micron-sized, Dragon-green fluorochrome co-labeled iron-oxide particles [28], [29], [36], we were able to proof the MRI findings and to confirm the presence of the transplanted cells within the fetal myocardium. Using specific antibodies to either detect human cells, the fluorochrome co-labeled MPIOs or both, we were able to clearly detect the transplanted cells highlighting the efficacy of this cell-tracking approach.…”

“…Using novel micron-sized, Dragon-green fluorochrome labelled iron-oxide particles (MPIO) that had so far been used in the field of liver research [28], [29], we were able to evaluate human cell-fate after intra-myocardial stem cell transplantation on MRI which was then followed by detailed Flow Cytometry, PCR and IHC assessment highlighting the advantage of the fluorochrome co-labelled MPIOs. On MRI, the MPIO labeled cell-clusters were clearly visible within the septal and anterior-lateral ventricular-wall corresponding to the injection sites.…”