Magnetic resonance imaging (MRI) is the most frequently used technique for serial in vivo cell tracking applications due to high resolution of soft tissues, which makes it especially useful for imaging of the brain, muscles, or the heart.¹ In order to improve detectability of transplanted cells and produce a strong contrast against surrounding tissue, intracellular labeling of cells with iron oxide particles before transplantation has been described.² Our newly developed FeraTrack Contrast Particles are superparamagnetic iron oxide (SPIO) particles specifically formulated for in vitro labeling of various cell types prior to transplantation and pre-clinical MRI. Once within cells, SPIOs can induce decreased signal intensity on T1, T2, and T2*-weighted images.³
The FeraTrack labeling kit was optimized for proper in vitro labeling of cell lines (NIH-3T3, Jurkat), primary cells (granulocytes, neural progenitors), and stem cells (hematopoietic, mesenchymal, and embryonic stem cells) from different species (mouse, human, rat). Similar results were obtained with differentiation assays comparing labeled and unlabeled stem cells indicating biocompatibility of intracellular labeling. Feasibility of the newly developed contrast particles for MRI-based in vivo cell tracking has been evaluated exemplary by transplantation of mouse neural progenitors and rat granulocytes.
FeraTrack is not applicable for intracellular magnetic labeling of natural killer (NK) cells.
Schematic diagram of a FeraTrack nanoparticle.