Electron paramagnetic resonance as a sensitive tool to assess the iron oxide content in cells for MRI cell labeling...

Area of Science:

• Biomedical Imaging
• Biophysics
• Cell Biology

Background:

• Magnetic Resonance Imaging (MRI) is a key technique for in vivo cell tracking.
• Accurate quantification of iron oxide nanoparticles in cells is essential for validating MRI cell tracking studies.
• Current quantification methods have limitations in sensitivity and specificity.

Purpose of the Study:

• To implement and evaluate Electron Paramagnetic Resonance (EPR) spectroscopy for quantifying iron oxide concentration in cells.
• To compare the sensitivity and specificity of EPR with existing methods like Perls' Prussian blue reaction, ICP-MS, and fluorimetry.
• To assess the suitability of EPR for ex vivo analysis following in vivo cell tracking.

Main Methods:

• Cells (melanoma, renal adenocarcinoma, fibroblasts) were labeled with fluorescent iron oxide particles.
• Iron oxide concentration was quantified using EPR spectroscopy.
• EPR results were compared with Perls' Prussian blue reaction, ICP-MS, and fluorimetry.
• Limits of detection for each technique were determined.

Main Results:

• EPR spectroscopy demonstrated high sensitivity for iron oxide quantification.
• EPR measurements were specific for iron oxides and not influenced by endogenous iron.
• EPR showed a lower limit of detection compared to other tested methods.
• The technique is well-suited for ex vivo tissue analysis post-MRI cell tracking.

Conclusions:

• EPR is a sensitive and specific method for quantifying cellular iron oxide concentration.
• EPR can validate MRI cell tracking studies by confirming iron oxide levels in cells and tissues.
• This technique offers advantages over traditional methods for iron oxide quantification in cell biology and biomedical research.